Garage door sensor

[alsinha]

I have a new home with a Liftmaster garage door opener. This morning my dog decided he didnt like how the sensor was wired so I'm left with two sensors - one that has two wires coming out of it (sounds normal) and the other one that has no wire attached to it at all (awesome!)....Anyways, upon inspection I found there were 5-6 different wires coming out from behind the drywall that were probably connected to the two wires on the sensor. Would anyone here know (or be able to check) how the wires are supposed to be connected. I'm guessing 4 out of the 6 wires are 'dead-ends' and only 2 are connected to the sensor?
Thanks a lot!

[sillysod]

take a multimeter and check for dc voltage between 2 wires. those will be the wires that you need.

or if you don't have a multimeter just try connecting different wires until the light comes on in the sensor. it's all dc voltage and there is no way you can damage the system by using a trial and error method.

[AndyL]

Just check the wire colors at the opener and match... you won't find. Power on the newer openers as they use a funky serial data scenario for UL325 compliance.

[alsinha]

Thanks....I wasnt sure if I'd damage the opener using the trial and error method but I'll give it a try as i don't have a multimeter

[sillysod]

Originally posted by AndyL
Just check the wire colors at the opener and match... you won't find. Power on the newer openers as they use a funky serial data scenario for UL325 compliance.

Some of the openers are serial, but they are talking about the photo eyes.