# Trouble with Craftsman Garage door sensors, can I bypass??



## theway146

I am trying to fix my roomates garage as a surprise while he is on vacation... It's a Craftsman 1/2 hp auto garage unit, standard setup with the factory laser sensors at the bottom of each guide rail. The left one is green, no light at the right side. I want to bypass the sensors and try not buying new sensors. 

I've checked all the connections and they are fine. The right side loops up and around the door to the left sensor (the working one). There are a black and white wire coming from each sensor, which in turn is spliced into the wire going to the main unit (in logical unison, 2 blacks from each sensor going to "unit" blue; 2 whites from each sensor going to "unit" white).

I can see where the wiring makes sense, having the sensors loop into the unit wires in unison. I figured I could just bypass this and connect the "unit" blue and white to complete the circuit. This did not work. 

SO, is there a way to not use the sensors and complete the circuit and fool the main unit????


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## Drabdr

Welcome!!

Is the green light continuously on, or does it blink? How do you know it's the sensors? Will the door work if you hold in the wired button? Is there any movement at all on the door? 

Did the opener ever work at any time?


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## wacor

I tried bypassing mine with no luck

Try taking them off and putting them together where you know they are aligned. That way you know it is the sensors.


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## mrss

The receiver and transmitter go to the same two screw terminals, right? I don't believe you can't bypass that kind of safety sensor with a wire as the single pair of wires probably carries both the power and a simple digital signal superimposed on the power. 

They cost around 40 bucks, by the way.


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## theway146

Drabdr said:


> Welcome!!
> 
> Is the green light continuously on, or does it blink? How do you know it's the sensors? Will the door work if you hold in the wired button? Is there any movement at all on the door?
> 
> Did the opener ever work at any time?


What do you mean by "hold in the wired button"?

The green light is continuously on. The door use to go about 4 inches while holding the wall unit button down then would want to go the up direction... I use to be able to let go and then press right away and the door would start going back down. This would sometimes have to be done 2 or 3 times. The other day this method just stopped working. I've lived at this house about 3 months, but just started keeping my car in the garage for 2 weeks; it has always been this way for me. I do not know for sure it is the sensors, just a guess cause the one light is out.


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## theway146

wacor said:


> I tried bypassing mine with no luck
> 
> Try taking them off and putting them together where you know they are aligned. That way you know it is the sensors.


That's a great idea!



mrss said:


> _*The receiver and transmitter go to the same two screw terminals, right? *_I don't believe you can't bypass that kind of safety sensor with a wire as the single pair of wires probably carries both the power and a simple digital signal superimposed on the power.
> 
> They cost around 40 bucks, by the way.


I am going to take pics tonight of the setup tonight to hopefully answer your question.

Thanks again everyone!


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## wacor

theway146 said:


> What do you mean by "hold in the wired button"?
> 
> The green light is continuously on. The door use to go about 4 inches while holding the wall unit button down then would want to go the up direction... I use to be able to let go and then press right away and the door would start going back down. This would sometimes have to be done 2 or 3 times. The other day this method just stopped working. I've lived at this house about 3 months, but just started keeping my car in the garage for 2 weeks; it has always been this way for me. I do not know for sure it is the sensors, just a guess cause the one light is out.


maybe the adjusting force needs adjustment?
http://www.constructiontrends.com/articles/3767/1/Adjusting-A-Garage-Door-Opener/Page1.html

I assume your springs are ok and you can open the door manually with no difficulty?


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## theway146

wacor said:


> maybe the adjusting force needs adjustment?
> http://www.constructiontrends.com/articles/3767/1/Adjusting-A-Garage-Door-Opener/Page1.html
> 
> I assume your springs are ok and you can open the door manually with no difficulty?


Thanks, I have copy and pasted that and printed for later reference. Yes, the springs are great and once I budge the door manually a few feet the door goes up smoothly.


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## wacor

theway146 said:


> Thanks, I have copy and pasted that and printed for later reference. Yes, the springs are great and once I budge the door manually a few feet the door goes up smoothly.


you saying it goes up automatically after you give it a hand?

if so then I bet it is the adjusting force


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## theway146

wacor said:


> you saying it goes up automatically after you give it a hand?
> 
> if so then I bet it is the adjusting force


No, sorry for the confusion, it goes up easily with me continuing to push and released from the chain (and unplugged now).


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## Drabdr

theway146 said:


> No, sorry for the confusion, it goes up easily with me continuing to push and released from the chain (and unplugged now).


Ok... with the door unlatched, does the opener go back and forth? Does the screw drive appear to drive the "holder (connects to the door) back and forth?

My wired button is the reference to the wall unit button. Sorry for confusion.

Generally, if the sensors are not working, or the beam is broke, you cannot get the door down. But, I _believe_ the door will go up, but don't quote me on that.

Like Wacor mentions, that force sensor adjustments can really wreak havoc on those things.


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## theway146

Drabdr said:


> Ok... with the door unlatched, does the opener go back and forth? Does the screw drive appear to drive the "holder (connects to the door) back and forth?


Oh, I did that troubleshoot. With the door unlatched and down, the chain still does the same thing. It moves about an inch or so, then comes back.



> ...My wired button is the reference to the wall unit button. Sorry for confusion.


So, back to your original question, will the garage work by holding in that button. Yes, but only by letting go of the button and quickly reapplying when the door starts going the wrong direction. This "feathering" use to get the door down but it stopped working the other day.



> ...Generally, if the sensors are not working, or the beam is broke, you cannot get the door down. But, I _believe_ the door will go up, but don't quote me on that.


Well, seems like we might be at that point. I should point out that before I started keeping my car in the garage my roomate used the door about once a month. In the last three weeks, I've used it about 60 times, 3 years worth for him.


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## theway146

Here is the wire setup at the machine, both of those white telephone looking cords are coming from the loop near the sensors. One of them controls power to the wall unit button. The next picture will show the harness at the sensors with similarily colored wires.










This is the "tele" wire at the sensors, in it's current state where I tried to bypass the sensors all together and connect the blue and white. No workie...


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## Noyb

The sensors work very well mounted here ...


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## theway146

Noyb said:


> The sensors work very well mounted here ...


 I like the ingenuity! :up:


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## wacor

I taped mine together


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## Noyb

Is this what Ya'll wanted to see ???

The White wire is gnd
Vert is 2V/div ... 0V is centered
Horiz is 1ms/div

I don't think it can be simply bypassed


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## JohnWill

Bypassing those sensors seems like a bad idea to me in any case!


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## Drabdr

Hey all!

Yea... it's tough bypassing those sensors.

I'm still not totally for certain it's the sensors. I'm thinking like Wacor, that it may be the force adjustment.

I would adjust the force sensor all the way to maximum. Are there wired limit switches? they may have to be moved. 

You said the chain stops at an inch. Is it exactly an inch? I had to replace my mom's opener, because there was a worn spot. Just kinda digging around on this.


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## theway146

Drabdr said:


> Hey all!
> 
> Yea... it's tough bypassing those sensors.
> 
> I'm still not totally for certain it's the sensors. I'm thinking like Wacor, that it may be the force adjustment.


Aren't both sensors supposed to have a light on?? The right side has the "bulb" but no light.



> ...I would adjust the force sensor all the way to maximum. Are there wired limit switches? they may have to be moved.
> 
> You said the chain stops at an inch. Is it exactly an inch? I had to replace my mom's opener, because there was a worn spot. Just kinda digging around on this.


I'll try the force sensor. Don't know about the wired limit switches. The inch was an estimate... It goes just briefly (with door attached or not) then retracts back.

Wouldn't the force sensor be irrelevant if there is no door on the chain??


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## Noyb

Aren't both sensors supposed to have a light on?? 
Mine have both LEDs on .. one amber .. one green

Wouldn't the force sensor be irrelevant if there is no door on the chain??
I would think it would have no effect .. unless there's a problem in the gear train.
That's what Busted in mine (for the second time) .. So I just got a new opener last week


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## Drabdr

theway146 said:


> Aren't both sensors supposed to have a light on?? The right side has the "bulb" but no light.


I have seen different kinds. Mine now has just one light on one sensor; the other one doesn't have any light.



theway146 said:


> I'll try the force sensor. Don't know about the wired limit switches. The inch was an estimate... It goes just briefly (with door attached or not) then retracts back.
> 
> Wouldn't the force sensor be irrelevant if there is no door on the chain??


You would think the force is irrelevant, but you never know.  Those limit switches may be messing it up; or you could have a worn spot on the track.


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## JohnWill

Both sides won't have a light, one is the photoelectric cell that senses the light from the other one.


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## Noyb

We may have different models, mine is about a week old, so we my have some differences.
The beam is infrared - it can't be seen
The sending unit has an amber LED - and the receiver has a green LED indicator to indicate power.

When the beam is obstructed .. and you try to close the door ..
the Opener lights will flash and you will hear a loud clicking sound (in case you don't have lights installed)

When I tried to Scope the signal .. I was obstructing the beam with two layers of thick electrical tape...
and I could not obstruct the beam. I had to remove one sensor and point it away.
That must be one strong infrared beam.


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## AKAJohnDoe

As a tangental post interjected into this thread, I had a single old garage door opener that was opening two garage doors that was having problems (worn out) and we lived with it for several years, having to get out in the rain to "help" it open.

It tried to kill me this year. Closed and would not reverse.

I got a pair of new openers, one for each door, single three button control.

Garage door goes up, garge door goes down, Garage door goes up, garge door goes down, Garage door goes up, garge door goes down, ...


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## Drabdr

AKAJohnDoe said:


> Garage door goes up, garge door goes down, Garage door goes up, garge door goes down, Garage door goes up, garge door goes down, ...


Whew!! I had to stop reading! I was getting dizzy!!

My finite experience with those sensors is that the door will not move automatically with the beam broken. The one I had, you could get the door to do down by holding the wired button (button on the wall). You could get it to go up.

So my door required some adjusting on the force sensor. My mom's door had some teeth wear out on the main gear that traverses the screw.

Can you see where any of the track is coming loose? The more I think about this, the more I'm wondering if it's mechanical. The door was working fine, had been used a whole lot, no one adjusted anything, then stops working correctly. Sounds like a part wore out, or went out.


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## buck52

JohnWill said:


> Both sides won't have a light, one is the photoelectric cell that senses the light from the other one.


Both mine have lights on both sides

Two doors and two completely different openers...


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## JohnWill

You're talking about pilot lights, that makes sense.


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## JohnWill

Noyb said:


> When I tried to Scope the signal .. I was obstructing the beam with two layers of thick electrical tape...
> and I could not obstruct the beam. I had to remove one sensor and point it away.
> That must be one strong infrared beam.


You used the wrong tape. You just need a think layer of aluminum foil wrapped over it, it'll stop the IR beam cold. I've had a similar experience with IR sensors and electrical tape.


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## Noyb

JohnWill said:


> You used the wrong tape ... I've had a similar experience with IR sensors and electrical tape.


Where were you when I needed you  ???
You could have saved me a lot of work and confusion 
All the indications were .. The tape was invisible


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## JohnWill

Correct, IR will penetrate many types of tape, I was stunned at how well it blew right through electrical tape too.


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## buck52

JohnWill said:


> You're talking about pilot lights, that makes sense.


pilot lights?

If I break the path between the two lights the door goes back up...


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## theway146

Well, a dandy of a thread we have goin here! 



Drabdr said:


> ...Can you see where any of the track is coming loose? The more I think about this, the more I'm wondering if it's mechanical. _The door was working fine_, had been used a whole lot, no one adjusted anything, then stops working correctly. Sounds like a part wore out, or went out.


Actually, just this morning as I was doing the manual push up (man it takes some muscle to get it going!) the right side came off track. Son of a gun almost didn't let my car out! I am trying the force sensors this afternoon.

To recap though, I do not know how long the door had been acting up. My roomate says he had been doing it for a while (him having to keep the button pressed to get door down and feather it). It got worse progressively with my daily use, to the point where the button holding/feathering did not work!


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## wacor

thought you said the door went up easily manually??

you sure you don't have a broken spring

are your springs vertical on the sides or horizontal over the top?


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## theway146

wacor said:


> thought you said the door went up easily manually??
> 
> you sure you don't have a broken spring
> 
> are your springs vertical on the sides or horizontal over the top?


Very easily once I get past that first few inches. I will check the spring layout today as well...


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## wacor

if the springs are overhead they are not as obvious to see they are broke as the ones on the side. IMO

By that I mean they are not as visible so easily ignored.


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## JohnWill

The springs don't have to be broken to be defective. Many times old springs will stretch. In the 20 years I've been here, I've replaced all the springs on the three doors, and at least one of them is looking like it's time for another set of springs. You can normally tell if they're getting bad just by looking at the length of all the springs and seeing if any of them are longer than the others, especially if you have multiple doors.


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## theway146

JohnWill said:


> The springs don't have to be broken to be defective. Many times old springs will stretch. In the 20 years I've been here, I've replaced all the springs on the three doors, and at least one of them is looking like it's time for another set of springs. You can normally tell if they're getting bad just by looking at the length of all the springs and seeing if any of them are longer than the others, especially if you have multiple doors.


Here is my spring setup as promised...










As you can see, I have it disconnected from the chain, so wouldn't items such as the force sensor and springs be irrelevant??

With it disconnected the chain still only moves a few inches then comes back...


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## Drabdr

theway146 said:


> As you can see, I have it disconnected from the chain, so wouldn't items such as the force sensor and springs be irrelevant??
> 
> With it disconnected the chain still only moves a few inches then comes back...


Well... you would think.  All I know to do is make sure it's disconnected, turn the force sensors to max, and see what happens.

The door itself looks like lightweight metal. Are you able to easily lift it up?


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## Noyb

Sounds like its time to remove the opener and put it on the floor.
Park it in the full down position when you do this.
Hint  New Openers are on sale this week.

Id try one more time with the chain removed to see if theres any binding in the track/chain.

Id suspect a transmission problem .. 
these are common failures and Sears usually has spare parts on hand  it they still have a service dept.
Ive had to fix my previous opener once.

The top gear #3 is usually plastic .. So it will strip easily and save the opener.
The worm gear #3 is metal .. as I remember.
Since the top gear is designed to strip easily ... I cant imagine that this would bind and stop (overload) the force sensors.


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## JohnWill

Your spring is the torsion bar type, mine are the dual springs that are on each side of the door.

I've never had one of those types, though I'm pretty sure you have to replace those periodically.

If the door operates normally without excessive force manually, it's probably not the springs anyway.

As far as the opener going only a few inches and then stopping, it the door doesn't move, it may confuse the logic, assuming the sensors are working. With the door disconnected, I'm not sure what it'll do. Did you try operating it with the door up as well as down while disconnected?


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## wacor

just a heads up to the OP

do not touch those springs unless you have somebody who is familiar with adjusting them. there is a ton of tension on those and it is easy to do serious harm or worse if something slips. 

I have those kind of springs and have had two break in the last 10 years. they need to be oiled periodically. it is pretty obvious when one is broken and it will be separated. and the door is very hard to lift. 

as I recall you said the door went up easily for a short bit and then was difficult ????


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## Drabdr

JohnWill said:


> Your spring is the torsion bar type, mine are the dual springs that are on each side of the door.
> 
> I've never had one of those types, though I'm pretty sure you have to replace those periodically.


Yea... those torsion bar springs are a bear. When they break and you have a heavy door... better plan on staying in for a bit. Too, It requires a special tool to crank the spring to the proper level for tightening. I've always just got someone do change those out.

Your suggestion about changeout is probably a good one. I just let it go until they break.


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## Drabdr

Wacor... sorry my post sounds strikingly similar to yours. You beat me to the posting punch!!  It's good that great minds think alike.:up:

If that spring is broke, you'll know it. Not only can you see the spring (part of it) not moving, that door will be extremely difficult to lift.


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## wacor

the tool is nothing special. you can use a piece of rod that is about 3/8" OD to adjust. But you need two of them and a steady hand. if one slips out before you get the other in the next hole you can get killed when it flies out. I have a solid door and it is all I can do with a 2nd hand to get the door up.


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## JohnWill

Judging from looking at those several times at a friend's house, I think I'd have someone else change them too!  The standard side springs are not difficult to change, since they have no tension on them when the door is up, you can just unhook them and slip the new ones in.


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## Drabdr

wacor said:


> the tool is nothing special. you can use a piece of rod that is about 3/8" OD to adjust. But you need two of them and a steady hand. if one slips out before you get the other in the next hole you can get killed when it flies out. I have a solid door and it is all I can do with a 2nd hand to get the door up.


Yea... you lost me on the "get killed" part!! He! He!

I've seen them use a cranking wheel to do this. You're right, though, come to think of it. You could do it yourself. It's just a bit out of my comfort level, though.


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## theway146

Well, my contractor friend came over last night and we think it is the sensor for sure. We pulled the right sensor all the way over and butted it right up, no light. Then we pulled the left sensor which IS getting a green light and put it on the other wire, and it still lights up green (proving wire is okay). So, when the owner of said garage gets home I'll tell him to get some new sensors! 



Drabdr said:


> The door itself looks like lightweight metal. Are you able to easily lift it up?


Friend pointed out it is insulated and heavier than normal...



JohnWill said:


> If the door operates normally without excessive force manually, it's probably not the springs anyway.
> 
> As far as the opener going only a few inches and then stopping, it the door doesn't move, it may confuse the logic, assuming the sensors are working. With the door disconnected, I'm not sure what it'll do. Did you try operating it with the door up as well as down while disconnected?


Will try tonight...



wacor said:


> just a heads up to the OP
> 
> do not touch those springs unless you have somebody who is familiar with adjusting them. there is a ton of tension on those and it is easy to do serious harm or worse if something slips.
> 
> I have those kind of springs and have had two break in the last 10 years. they need to be oiled periodically. it is pretty obvious when one is broken and it will be separated. and the door is very hard to lift.
> 
> as I recall you said the door went up easily for a short bit and then was difficult ????


Thanks for the heads up. I am ambitious but not that much!

The door is hard to pull up the first foot THEN is easy...

Thanks for all the help!


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## JohnWill

Well, typically, my doors are a "bit" harder to start manually, but not all that hard. It should not be a strain to open the door manually, or the opener will have a real problem.

I saw an opener that ripped itself off the ceiling and dropped on the top of the car in the garage when the door jammed, that was ugly. It was an old opener (circa 1970), and obviously any safety devices to limit torque didn't work. You can imagine the owner was more than a little bummed out!


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