2004 C5 stock coup. Turned key to on. Dimmed dash lights flashing including security light, but battery voltage good. Go to start position and hear loud clicking sounds like starter solenoid is engaging into a completely shorted starter, but battery voltage remains good during this test. Checked starter at two different part houses and it passed testing 6 times. Cleaned all 13 grounding points in car.
Next time car starts and runs fine. Shutdown and the next day it is turned on there is a clicking relay near passenger side and once again the dash lights are all flashing real dim. Clicking eventually fades away and dash lights go completely out. Going to the start position does nothing. No sounds. Nada. Putting the car in neutral and pushing a few feet. The car starts up and runs fine. Next time I try to start it is acting up all over again.
The Codes are for the A0-LDCM are
B2252H
B2282H
B2286H
B2284H
U1255H
U1064H
U1016H
U1096H

The Codes for A1-RDCM are
B2283H
B2287H
B2285H
U1255H
U1064H
U1016H
U1096H

No other codes were recorded.

I reset all codes. Kept switching ignition from on to off to on until the passenger side relay started clicking and dash lights flashing. Car won't start Turned ignition switch back to off and then on a few times until the dash lit up normal. Checked and there were no codes at all recorded and car starts and runs normal.

I'm now thinking that I have a bad ignition switch. Any advice would be greatly appreciated before I go down that rabbit hole.

 

WELCOME to the Forum !!...when I had what I thought was an ignition switch problem I selected battery volts on the DIC and when starting I was only seeing 7-8 volts…that’s why you were seeing your dash lights go out…IPC voltage was low…I cycled the switch a bunch of times to clean up any bad contacts in the switch and the car started…try that and if you have a DVOM and some basic electrical knowledge we can do some testing to confirm it’s a bad switch...can you fill out your profile with model year, mods, tune etc...this helps us help you down the road.

 

C5 Diag,

Thanks for the welcome and the quick reply. I turned the ignition to on and got nothing. No dash lights, no clicking. Absolutely dead. When to start and still got nothing. I turn the switch off and back to on, three or four times with nothing. The next time I went to on and the dash lights came on and everything looked normal. I set it to read voltage, Read 12v. went to start, the voltage display went blank, car cranked and started, and then displayed 12v and quickly went to 13.8v. I did cycled the car off and restated three or four times and each time everything worked great.

It all looks fine now, but I'm pretty sure it act up again after awhile. This is my wife's car and she hardly ever uses it. It did have a glitch when she was driving it about a year ago where it went into limp-home-mode. She had to abandon the car and wasn't at all happy. I never was ever to get it to do that again and didn't research enough to know why it did that. I don't think she has driven it since.

I hadn't reset the stored error codes until just this afternoon. Would any of those codes I listed indicate what happen a year ago to cause it to go into limp-home-mode? Is there a link to a guide where I can look up those codes?

What do you think? Ignition switch?

I added all my info on my profile, but it doesn't show up when I post. I guess there is a trick here that I need to learn. I'll figure it out.

 

Well this may be an issue with your battery cables…you have a DVOM and know how to use it ??…I would do a voltage drop check on the positive and negative side of the cables…you will have to get underneath the car to check this.

 

As C5 diag stated it could be loose battery cables or bad battery cables, check connections at battery,starter solenoid, engine fusebox power connections and the negative battery connection located above the starter. If none of the above suggestions corrects the problem it could very well be the Ignition switch.

 

I do have a DVOM and did check voltage and did R and R the starter and battery, cleaned all connections and tested the starter multiple times. I also cleaned all ground connections and positive cables to fuse and relay box.

This morning the car started and ran perfect twice in a row. The voltage comes on at 11.8v and goes to 14v. when the engine is running. The third time I tried, when the key goes to the on position I hear a relay pulling put no power to the dash gauges and lights. The interior lights and head lights work fine. Going to the start position does nothing but I do hear a relay. I cycled the ignition at least a dozen times with just hearing the relay, but no power to the gauges.
I
waited a few hours and once again the car worked normal the first try and then failed on additional attempts.

I'm now thinking the relay I hear on the passenger side is operating but the contacts aren't always making a good connection.

Any thoughts how I can check to verify the ignition switch and that the ignition relay is working properly?

 

Take your DVOM and with it being on a low voltage scale place the red lead on battery positive…take the black lead and touch it to one of the 2 metal test points on top of IP fuseblock fuse 19 (IPC) while trying to start the car…you shouldn’t see more than 0.2 volts…if you see 7 volts that means you only have 5 volts available to that circuit…7 volts is dropping across the ignition switch…also do this on BCM fuse 9, CRK fuse 14 and BTSIBU fuse 21.

 

Thanks C5 Diag,
The situation has changed and now it either starts and runs fine or it doesn't even power up. None of the fuses you mentioned even become energized when it not working. I found this video that is exactly like my car...
I tried his advice and pushed in on the key and it fixes the problem and the car starts and runs fine. Has anybody had this issue and was able to fix it without replacing the ignition switch?

 

There is a sticky on this site which details the removal of the ignition switch and cleaning of contacts within the switch, or buy a new one, but beware there are many Made in China switches.

 

The voltage drop method I explained doesn’t tell you if the circuit is being powered…it just tells you the voltage that is being dropped across the ignition switch which should be .1 to .2 volts…are you checking it the way I explained it ??…some find it difficult to understand that you can read some type of voltage with both multimeter leads on either the positive or negative side of a circuit…you can check the voltage the “normal” way and see what your voltage reading is on each of the fuses..each one of those fuses come from a different ignition feed wire…if you watched the SMA video you can see those heavy gauge wires on the back of the switch….pink, yellow, brown and orange…JUST REPLACE THE SWITCH !!…get an OE (AC Delco) one from NAPA or Rock Auto…stay away from aftermarket ESPECIALLY Dorman.

 

With the voltage coming on at 11.8, that would be about a 35% state of charge of the battery. How old is the battery, what type? C5's have electrical gremlins if the voltage is low. The car will start but the electronics/modules aren't happy.

 

Thanks for all the advice everybody.
It became obvious that my problem was in the switch.
My battery is new, but I was using a lot of energy out of it trying to sort out the problem without driving it anywhere, it did get low.
Since the ignition wasn't supplying power, there also wasn't any voltage drop across the ignition switch contacts. No current = no voltage drop.
After installing a new Delco switch from Rock Auto and resoldering the 8 resisters in the climate control unit, everything is working great again.