Do you have a test light or multi-meter to do some testing?
Thanks, Carguyjosh
Can I get you to first check the 60 amp ( I believe it fuse #3) in the fuse block on the right front strut tower. Be sure to make sure that there is power going through it...
Can you tell me, when you hit the defog button, can you feel a click in the defog relay?
Please let me know...Thanks, Carguyjosh
I am sending the wiring diagram to reference, more tests to follow...
Next, what I need you to check is with the relay removed, test light connected to a good ground,
I need you to check that there is power from the 60 amp fuse and then also power from the defog switch when you press the button. These tests are done at the relay plug with the relay removed...
Please let me know what you find...
Josh
I get 12v coming in at top right pin. 0V below that pin. I get about .5V constant at pin to the left of the 12V pin and oV on lower left. No voltage change when button is pushed to any of the other three posts.
Wayne
Okay, there is one more check that I would like you to do. I would like you to connect your meter positive lead to battery power and test the 3 pins that did not have 12 volts.
What we are loooking for is when you push the switch, the switch is not sending a ground signal to the relay instead of a power command...
In my opinion, the diagram is poor in the regaurds of current flow...
There are only 2 possibilities if the ground signal is not switching. The controller is bad or the engine control computer is shutting down the system.
Of course, all of the flow charts want information that you must have a scan tool to access...If we don't find a ground switch, it will be completely up to you wether you want me to send an answer to accept as I can't tell you 100% that a new controller will fix the problem...All I can tell you is that the most likely cause would be the controller failing...
Please let me know what you find.
The right lower terminal is switchable and completes the curcuit when the button is pushed. The two to the left make no difference with the switch they complete the curcuit on contact with the probe so I get 12v all the time when the ones on the left are touched. By the way how should the relay go in it will go in two different ways.
The relay will not make a difference on which way it is plugged in...
I think that we can't go any further without a scanner. With everything that I have had you check, we know that the controller is sending the signal, we know that the 60 amp fuse is good but what we do not know and can't find out is if the body control module has shut the system down for some reason or the module itself is bad...
We would have to have a scanner for body diagnostics...
I'm sorry I can't take you further in the diagnostics, we now have computers running computers, if one is not happy, it affects them all...
You will have to go to a shop with the abilities to scan the body control system on your car,.,,
Thanks for your time and testing......Carguyjosh
It has to be a dealer type of scanner. The OBDll scanner can only read engine codes. Now I have the GM Techll scanner and the Snap-on MODIS scanner. Both will read body information and codes so you do have to go to the dealer, you just need to ask your local garage if they have the scanner needed to diagnose body computer problems.....
Thanks Again....Carguyjosh
ASE Certified Technician
ASE certified , 16 yrs in field