Bill Curlee

The wire colors are RED All battery feeds are RED:



Did you check the battery?? Check voltage, connections and battery terminal tightness.



How about ground to the chassis at G-104/108

Bill Curlee

I sometimes see people that are looking for a power souce that is controlled by the Ignition Switch. 97-2003 C5 have a dedicated aux power connector specifically for powering aux equipment. Its to the left of the BCM and if it has never been used, it will be wrapped in black or silver tape. The wires are yellow, orange and black. Orange is hot at all times, yellow is ignition switch controlled and black is ground. They are 20 Amp fused. There is a connector for these wires and it can be seen in the picture:





There is ONE more. If you have a 2004 C5, you will not have the aux wires mentioned above. However, there is an UN-USED pin in the ignition switch that you can add a pin to the female connector and have a switch 12VDC source. ALL C5s have this spare ignition switch terminal. You will have to add a pin and a wire to the ignition switch connector.



Bill

Ppags

Also this might be a dumb question... Can I leave the cigarette lighter, truck switch, and air temperature sensor unplugged while I trouble shoot the problem?

Bill Curlee

Yes,,, the trunk switch and the temp switch may leave a DTC

Ppags

That's fine, I just wanted to make sure that wouldn't cause the alarm to go off. I'm going to check the ignition wires tomorrow to see if they're getting proper power. And take apart the switch again. It's hard to trouble shoot what I did wrong with it going off killing the battery. I had to hook something back up wrong, or accidentally disconnected something to set it off

Ppags

Ok so I had a little time this morning while my daughter was still sleeping to mess around in the garage. Before I put the battery in the car I checked it with the multimeter, read 11volts. Next I pulled all of the fuses that have anything to do with the ignition to check if they were visibly blown, they were not. Next I'll check for continuity, I didn't think of it this morning. Then I moved to the ignition wiring. Now there are 2 plugs that connect to the bottom of the ignition module. 1 black, that goes on the right, which has 5 wires going into it( 1 for each connector). But the white connector on the left only has 4 wires going into it. I checked everywhere to see if there was a loose wire that may have fallen but didn't see one. Is that normal for it to be missing? After checking the wires I plugged everything in, and made sure the connections were good. Next I plugged in the battery, that stupid clicking sound started up again( still not quite sure what it is but it's coming from the driver side front tire area somewhere). Anyway, I checked the terminals again once it was plugged in, 11 volts. Next I turned the key to the "on" position, which yielded no results still, no dash lights, radio etc. Next I check the fuses listed in Bills ignition module thread that are supposed to match battery voltage when the ignition is in the on position. They all read .3 volts. So I scratched my head a bit and then checked the wires going to the ignition module. No power whatsoever. Decided to 're check the battery again and it only read 6 volts now. So it went from 11 to 6 within a matter of maybe 3 minutes of it being plugged in. so the battery is charging now so I can take it to get tested and most likely I'll exchange it for a new one seeing as how it's not even a month old yet. I forgot to check the aux. Wires next to the bcm. So seeing as how I still have no understanding of how electricity works in this car I think I may need to call in some extra help to figure this one out so my baby doesn't sit in the garage forever.

Ppags

Are the 2 wires going to the tumbler lock supposed to be hot at all times?

Ppags

So the car has power now and will crank again,but still wont start. So im still at square 1 as far as the no comm issue. Everything is still saying no comm in diagnostic mode. Battery is brand new, load tested, and good, Every fuse is good, every ground checked, star connector for doors&seats is disconnected to rule that out, and ignition switch contacts are clean. When i turn the key to "on" there is a slight 2 second hesitation for the display to turn on that isnt there during normal operation, also once i remove the key from the ignition completely the display is still flashing service engine soon, low fuel, trans fluid and all that. Any ideas on what it could be?

uncle wilson

well doing some trouble shooting on my own tks !!!!!!!!!!!!!!!!!!!!!!!!!!

Bill Curlee

Are you sure that you have ALL the proper voltages out of the ignition switch???

Recommend that you measure the ignition switch supplied voltages for each of the things that dont work or are reporting NO COMMS.

Use a voltmeter and make sure that you have full battery voltage on each fused circuit.

The ignition switch connectors are well known for spread or damaged pins. When the pins spread they loose proper contact with the male pins.

If it were me, I would give those connectors a good look and make sure that they are not spread apart.

Bill

tfrederick74656

THANK YOU SO MUCH FOR THIS ANSWER! I had literally the exact same problem & solution. I have a minor water intrusion issue on the driver window, so every once in a while when it rains, I get a little bit of water on my seat - I guess this time there was a drop or two that rolled into the wiring. The moment I disconnected the power line to the driver seat, everything else started working. This no doubt saved me HOURS of troubleshooting, so THANK YOU!

Bill Curlee

Ok EXPLORER & tfrederick74656

Its time to OPEN UP that module and see if you can find any sort of circuit issue like Corrosion or damaged components. Take a picture and post it.

I LOVE solving these module issues. Many say that they cant be fixed. Sometimes they are right BUT,,,, Ive fixed a bunch.

Bill

emclass

Solved my problems as well, same issue. Thanks to all