I have a 2000 C5 corvette. I just changed carpet, cluster, and seats. Old cluster was scratched. When I went to start the car it would just click and not start. Now, if I disconnect the battery for about 30 seconds the car will start right up. After about a minute there is a clicking noise coming from the BCM area and the heat and air control lights and interior lights will flash in tune with the clicking noise, but the car will run fine. If I turn the headlights on and turn the dash dimmer all the way down the clicking will stop and so will the flashing. But after I turn the car off, the car will NOT start back, and the security light in dash will flash. And the clicking noise coming from the bcm area will start again and interior lights will flash. When I try to start it again, either nothing will happen or the starter will bump and immediately stop but not enough to start it. Just a quick bump of the starter is all I get. The car will not restart until after I pull the battery cable back off and wait for atleast 30 seconds. I have only had this car for 3 weeks, and I'm in way over my head on how to fix this. When this happened, I did change the cluster back to the old one or the original one. It does the same thing. It is reading several codes which mostly come up as loss of communication codes. I can't find anyone who even wants to work on it. Any help would be greatly appreciated. Thanks, Jamie

 

Sounds like a Battery problem to me. Have it load tested, make sure it is fully charged, then pull the trouble codes and post them here.

 

The battery is fine. I tested it first thing.

 

Did a load test on the battery. I have traced down everything I have done 5 times over and everything checks out. I have reset all the codes and these are the ones that now pop up since:

BCM:
B0605
B0502
B0507
B2482
B2587
B2592
B2723

TCS:
C1255
TCS C1255

SCM:
U1255
U1064

RFA:
U1096
U1064
U1016

SBM
U1000
U1040
U1096
U1064

LDCM:
U1064

RDCM:
U1064

PCM: No Codes
IPC: No Codes
Radio: No Codes
HVAC: No Codes

These are all the codes it is reading. I really appreciate all of your help. I am a girl, and I have been around cars all my life and am not car stupid but this one is beyond me. Thanks Jamie.

 

Your very first code, B605 is a serious issue. "B0605 BCM Internal Memory Function"

Were you having these issues prior to replacing the IP Cluster and Seats?

 

well today I erased and reset all the codes. I then took the car to oreillys to test the battery...the battery was 12.51 with the key off and 14.10 with the car running. Computer ripple was 6.5mv and it had a good load test. I then drove the car about 5-10 miles home and here are the codes I get... PCM- no codes TCS- C1255H BCM- no comm SDM- U1000HC, U1064HC IPC- U1064H, U1176HC, U1160HC RADIO-U1096H, U1064H HVAC- no comm LDCM-U1064H RDCM- U1064H RFA- U1064H these are all the codes it is reading now.. I am really dumbfounded on this one...I have sent Bill a message a few days ago but have not heard back from him...I just don't know what to do Jamie

 

Jamie, grab the rubber tubes between the doors and body of the car and shake the crap out of them. C5s have many "No Communication" codes because of bad connections in the wiring connectors just inside the lower A pillar. Then clear the codes and see what comes back, and post again.

 

Bill's Pictures! (He has a picture of every darn piece of a C5 Corvette.):----------------------------------------

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I have already tried that and I even put the liquid electrical tape that bill had recommended on another forum...is it okay to hardwire that connector though? No change

 

Today I put a brand new optima red top battery in the car today and nothing changed. Same symptoms. For the first time today when i was pulling into oreillys to get the new battery my message center read Low Voltage and a couple times now it has said reduce engine power. Do I have to buy a BCM from the dealer or can I buy one offline or from somewhere cheaper? Can I program it myself or do I have to take it to the dealer to have it programmed? I checked with the dealer here and they priced me $1900 alltogether. $1400 for the BCM and $500 for programming it. That seems a little high to me!

 

Put a meter across the battery, both while the ignition is off and again with the engine running and tell us what voltages you saw. With the ignition off, you need at least 12.5vdc. With the engine running, you should see anywhere from 13.8 to 14.3. At times, when the fans are running on high speed and you are idling, it might read all all the way down to 13.1. The electrical center of the car is actually at the starter solenoid. This is where the battery, alternator, fuse boxes and of course the starter, all come together. It sounds like you are having a BCM issue, but for the peace of mind, check the voltages. Remember that the solenoid connections are electrically hot. Lose, dirty or defective battery connections down there can cause lots of trouble.

 

dgrant- I have already put a meter to the battery with the key off and it was 12.5v. With the car running it was 14.1v I will check around the started solenoid to see if I see anything out of place. I do plan on checking the power going to the BCM tomorrow at the star connecters. Thanks Jamie

 

Yeah, the star connector would be next in the agenda but if its tight, look for evidence of water on, around or in the BCM.

 

Well today I think I might have made some progress. I have read several different forums on how to check the star connectors for low resistance and so forth. I checked the DLC pin #2 purple wire and the DLC pin #4 black wire with an OHM meter. It read 00.0. I then checked the star connectors with the OHM on the connector with the most wire's.These were the readings:
Light green-18.89m
White-37.8K
Pink-OL (nothing)
Blue wire with white stripe-OL (nothing)
Grey-134.9K
Blue-10.70K
Light Blue-109.5K
Orange-18.37m
Dark Green-OL (nothing)
Purple-OL nothing.

I then checked the star connector with only four wires and got these readings:
Purple-nothing
Brown-18.5m
Light Brown-16.76m
Brown white strip-nothing

I did notice on the star connector with 4 wires that the brown white striped wire had been pinched at some point. Its not real bad though. I can't see any wire exposed but something did pinch it. I also took the drivers seat back out and didn't find anything wrong.

I also rechecked the battery today and got these readings.
12.36 with key OFF
12.17 with key ON
14.42 with car RUNNING

I am supposing that I do have a problem of some kind since several of the wires were not having any readings. I am going to post below the forum I found and went by that was testing all these wires so you will have some idea.

Here is BlackZ06's post I went by:
Troubleshooting info for the C5 serial-data-bus : (by ersatz928)

Every module which talks on the serial bus has it own piece of wire which comes to a"star" junction. The star junction is where all the wires connect together, so all the modules can talk to each other. There are actually physically two star junctions, located next to each other, to the left of the BCM module. There are two because GM needed more wire connections than one star junction block could handle, there is a short wire that connects the two star blocks together. Each star is a black (or grey?) rectangular plastic block, with lots of wires on one side. It is really just a multipin connector which is plugged-into a shorting socket, which connects all the wires together.

C5 modules (and the databus wire color) on the serial-bus are :
BCM (Light Green)
PCM (Dark Green)
IPC Instrument Cluster (Gray)
DDM Driver Door Lock Module (also controls the window) (Brown)
PDM Passenger Door Lock Module (also controls the window) (Tan)
Radio (but not the CD Changer) (Orange)
Auto-Climate control head-unit/display (Option) (White)
RCDLR (Radio receiver for the Key-Fob transmitter and Tire Pressure sensors) (Pink)
SCM module for Memory Power Seats and telescope colum (Option) (Brown white stripe)
ESC Electronic suspension shock damping control module (Option) (Dark Blue with white stripe)
EBCM Traction Control/AH module (Light Blue)
SDM (Airbag control) module (Dark Blue)
The Star Bus also has a connection at the Data Link Connector (under the drivers side dash) where you connect a OBD2 code scanner to. DLC pin #2 (Purple wire)

There are three kinds of failures that can take down the whole data-bus :
1) One of the wires is shorted to ground, somewhere along its length between the star junction and the module location.
2) One of the modules has an internal bus-driver/receiver failure which forces a continious positive voltage on the bus.
3) One of the modules has an internal bus-driver/receiver failure which forces a continious low voltage (short to ground) on the bus.

This troubleshooting assumes there is only one shorting problem with the data bus wiring, or one module.
1) Disconnect the battery
2) Use an Ohm-meter (DVM, DMM, VOM..) to measure the resistance between DLC pin #2 (Purple wire, upper row, the pin to the left of the rightmost pin), and to chassis ground DLC pin #4 (Black wire, upper row, fourth pin to the left of rightmost pin). I think the measured resistance should be 5K (5000) Ohms or greater. If it measures at least 5000 ohms, you don’t have a short-to-ground on the data bus. If it is less than 5000 ohms got the next step. NOTE : I need to verify the 5000 Ohm go/nogo resistance.
3) Unplug the 2 BCM connectors. If the low resistance goes to 5000 ohms, the problem is internal to the BCM module, replace it. If the low resistance remains, re-install the BCM connectors and goto the next step.
4) Unplug the shorting socket from both Star connectors. Use your ohmeter to probe one wire at a time, to find the low resistance to ground. Identify the offending bus-wire and/or module by using the wire color associated with each module (see the module list above). 5)Find and unplug the module you identified in step 4. If the low resistance goes away, then that module has an internal short. If the resistance stays low, then the short is in the wire itself, somewhere between the Star block and the module location.

Note : The wire colors are from my 2001 factory service manual, I have not verified that they are the correct colors at the star connector blocks , or if they apply to all model year C5s.

Any ideas???

Thanks Jamie