rear deogger

[Poppa]

Hi all. First post here. I have a 94 Yukon ,we just got , and the rear window defogger isn't working. How does this actually work? I have 4 connectors coming off the rear window "struts" ,I get power out of the drivers side top one and then can't seem to go any further. Is that one the only power? Are the other three grounds? If I hook the test light to the power one and the other end to any of the other ones ,shouldn't I get a light? Thanks for your time.

 

[lesterl]

Do you have barn Doors or a liftgate?

 

[Poppa]

Lift gate.

 

[lesterl]

Each shock should have 2 wires, 1 at body, 1 at glass. One of the shocks will carry the ground, the other will carry the 12v. Check for 12v between the 2 shocks AT the glass.......

 

[Poppa]

If I ground a test light to the body ,I get power from the top drivers side wire. No where else.

 

[lesterl]

Ground the light to the other side....

 

[Poppa]

Nothing

 

[lesterl]

So you have a bad ground to one side, try the wire on the body side test light between the body side wires.....

 

[Poppa]

I'm sorry ,you lost me.?? Is there a wiring diagram of this somewhere?

 

[lesterl]

Struts mount to the glass at a point, mount to the body of the tahoe at a point. Wires comming off struts at glass and at body. Wires on body side should be tested to make shure there is power to the struts (testlight on one wire feeding strut on one side, ground clip to wire feeding strut on other.) If this is ok, move to the other side of struts and repeat, if it fails then one of the struts is not passing power along....

You will not have power on both struts as one side IS the ground for the circuit, the other side is the 12v Supply.....

 

[Poppa]

I will try this when I get home. I know I get power at the top drivers side. I don't think I get power at the bottom drivers side tho. Thanks , I will let you know.

 

[lesterl]

Yeah, need the power to travel the length of the strut and to the glass, they can go bad internally, also the tabs can come loose from the glass also....

 

[Poppa]

Must be the strut then ,no power at the bottom one ,drivers side. Thank you

 

[Poppa]

Hi again. How do I tell if I have a 1st design or a 2nd design?

 

[lesterl]

I dont understand the question, what design?

 

[Poppa]

I'm trying to order new "struts" for the rear window and have been asked are they 1st design or 2nd. They must have made a running change. Maybe different lengths or something???

 

[Poppa]

I did find two different ones. They are different lengths. Now to measure....

 

[lesterl]

Ah, glad I had the barn doors in a way, never had to deal with the struts....

 

[adam74]

I need to check mine out too. didnt work this weekend. first time Ive tried it since I bought the truck. thanks guys

 

[Poppa]

Ordered the 'struts' ,should get them today or tomorrow.