86 Calais Rear Window Defogger

[tweakerxp]

Well I removed the relay from the circuit and tested the window for ground and it was good. I'm really lost now

[maxwedge]

Either you are doing something wrong here or I am misunderstanding what you are saying, get the voltmeter on a window line on the b plus side of the defogger glass, then get the gd side of the voltmenter on to the ground connector for the glass and see whats what. Make sure there are no breaks in lines also. If you have 12v at the glass lines and a good gd at the other end of the glass, then either the purple wire has high resistance somewhere so the amps don't reach the glass or your lines are bad in the glass. What is the connection with removing the relay and checking the glass ground?

[tweakerxp]

Originally Posted by maxwedge

Either you are doing something wrong here or I am misunderstanding what you are saying, get the voltmeter on a window line on the b plus side of the defogger glass, then get the gd side of the voltmenter on to the ground connector for the glass and see whats what. Make sure there are no breaks in lines also. If you have 12v at the glass lines and a good gd at the other end of the glass, then either the purple wire has high resistance somewhere so the amps don't reach the glass or your lines are bad in the glass. What is the connection with removing the relay and checking the glass ground?

I'm sorry, but when you say B plus side, I really don't know what you're talking about. Anyways, the only time i have ever been able to get a voltage reading from the glass was by connecting my dmm to the PPL/WHT wire that eventually supplies power to the PPL wire at the window. (so PPL/WHT to PPL connector on window) Other than that, there's never been any voltage present. (either by testing for voltage via the connectors on the window or by grounding to the chassis and testing for power at the PPL wire connector on the window.) I figure there must be a break in the PPL wire. Any idea what the "C200K (WHT)" thing is where the PPL/WHT wire changes to PPL?

As for removing the relay, that was just so that I could isolate the ground for the window, so I knew it was actually the window that was grounding, not the connections at the relay.

[maxwedge]

The gd for the window is independent from the relay and just grounds the glass, if you have 12 on the ppl wire from the relay and it disappears before it gets to the glass, run a seperate wire from the relay just for test purposes and see if the glass works. Are you famliar with checking dcv circuits in a car, if not you better read up on it or you will get lost here, even though this is a very basic circuit.

[tweakerxp]

Originally Posted by maxwedge

The gd for the window is independent from the relay and just grounds the glass, if you have 12 on the ppl wire from the relay and it disappears before it gets to the glass, run a seperate wire from the relay just for test purposes and see if the glass works. Are you famliar with checking dcv circuits in a car, if not you better read up on it or you will get lost here, even though this is a very basic circuit.

Yeah I was actually just out looking at it, and was thinking i should do that. I bypassed the relay when i went out, ORN/BLK to PPL/WHT and no cigar. I'll have to pull off all the plastic trim from that side just to get at it, so I'll have to do it on a nicer day. I'm fairly familiar with basic circuits, so hopefully I can get by.