Remove the fuse and see if it is corroded or loose in the fuse connectors.

BC

 

Just ran out and checked fuse #19, fuse looked brand new, and so do the clips, no corrosion whatsoever, and fuse fits very snug into the clips. I went ahead and replaced with a brand new fuse just to be sure. same readings at the gauges as before.

 

If it is the stud ground on the frame just outside the battery compartment, then yes i have checked that one out when I was checking them all for any corrosion, but i will run back through those tomorrow, especially looking for any broken or frayed wires connecting to them.
thanks.

 

I was also curios if the problem may be the alternator, i've been doing some reading and it seems that the earlier C5's came equipped with a Valeo French alternator and has a data feed to the PCM which reads charging states and such, and it seems to be taboo to just put some aftermarket alternator on the car.....but i can't seem to find the Valeo nametag on this thing as it appears on others that i've looked up in search engines the tag should be right on top but it is not.......

 

C5 Alternators.

 

If you guys think it could be alternator related then he needs to run a jumper from the battery positive and negative posts into the car and directly monitor with a voltmeter what the running battery voltage is under load when driving. This should be easy and the wiring should be able to be routed between the hood and fender and thru the window. Nothing wrong with checking out anything that could be a cause, especially when it does not cost money to do it.

At this point I need to go back and re-read everything that has been covered so I fully understand everything up to now.

PS: I have plenty of info on alternator issues but one thing that shows up with a non correct alternator on the C5 is the Charging System Fault since they don't correctly talk to the PCM. Here is one post from Evil-Twin on this issue. If you need more I can provide including OEM part numbers by year.

 

If you have the incorrect alternator, it will show up as a charging system fault. You can measure the battery buss voltage in the cabin TWO ways:

Via the Cigar Lighter receptacle

OR

Via the AUX two wire power feed wires down near the BCM.

One wire is B+ Battery Voltage and the other is IGNITION SWITCHED voltage

The other wire is GROUND.

Measure the voltage there with a DC Volt meter and see if either wire acts like your IPC Voltages


If not,, you may need to remove the IPC and measure the voltages and grounds at the IPC Connector. If they are good there,, something may be wrong with the IPC.

You can disassemble the IPC and make sure that the connections from the IPC connector to the meter are TIGHT!

Here is a post that details the guts of an IPC

- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674

- C5 Gage Cluster Post - http://forums.corvetteforum.com/c5-t...post1570380878 http://forums.corvetteforum.com/c5-t...ansferred.html


Its easy to disassemble and check the connections and reassemble.

BC

 

If you have adequate actual charging voltage measuring directly on the battery terminals during engine run, No Charging System Fault messages and or no module low voltage DTCs, you are properly charging.

BC

 

Yes i was not trying to derail with the alternator comment, i find no invoices from the previous owner of any alternator being changed out, and he was the original owner and very meticulous paperwork he kept. I get no charging system errors or any faults or any codes in the DIC, the only issue that im experiencing is the low voltage readings on the analog volt gauge and the dic volt gauge. i'll check voltage at the cigar lighter and he aux wires in the bcm footwell here in a minute and post back.

 

So i guess it's time to check the IPC? I just checked voltage at the 3 wire Aux pigtails and at the cigar lighter, the battery shows 14.77 at the posts with engine running, and the constant hot and the switched hot wire each show 14.59 as well as the cigar lighter too, which is the same reading at the pink and red wires at the ignition switch and at fuse 19. so it appears i am charging just fine.

I double checked this ground and everything appears to be fine and corrosion free.

 

I was hoping you would not have to investigate the IPC but it is what it is as they say. I think Bill gave you all the info you need on the IPC. I sure hope you find something simple. However, there are a lot of IPCs out there if you need another. Or, if you need to have yours repaired I have several sites cataloged that I can send you if you end up in that situation.

 

Yes at this point, i don't know where else to look, i've checked everything and replaced the obvious, so i guess the IPC would be the next obvious choice, unless anyone else has any other suggestions.

 

Get that IPC OUT and get cracken!!!

 

First thing in the morning!

 

Well i pulled the IPC out and tested the connection and everything seemed to be fine there, the voltage was the same as it was at the ignition switch wiring and at fuse 19. I pulled all of the plugs out and inspected them and they all seemed to have a nice tight fit as well. So next, I bought an external automotive voltage gauge from the auto parts store and connected to the AUX Yellow/Black at the BCM in passenger floor board, i temp mounted the gauge on the column and i noticed when i turned the key on, the new gauge was reading below 12v and the car gauges were reading below 12v as well just like it has since the beginning of this post, so i went for a drive, at startup, the new gauge reads 14 volts and the battery was reading about 14.4, and the dash gauges both read 13.0-13.1 volts, i noticed after adding loads, the new gauge and the dash gauges would drop a bit dependent on the load, approximately the same number, just the new gauge was always reading about a volt higher.... is it possible that the gauges in this car have always read around 13? i was also reading that the PCM decides what the car needs as far as charging capacity too. It appears that if the car sits, i get a reading on the dash gauges of 13.1-13.4, and after a few errands (stopping and starting), the gauges will read around 12.9. but mind you i never get any codes, or any charging error messages, or any type of erradic electrical car behavior so back to not sure where to look at this point.

I even tore all the engine compartment grounds apart again, and buffed a clean mating surface on the frame and re attached all the grounds.

 

Just did a second test drive and the dash gauges never got over about 12.6. WTF.

 

If you pull the connector on the IPC and do a continuity test resistance reading on the ground pin C1 pin B13 to battery ground and chassis ground and it good and have a good voltage reading directly on the C1 pin A13 & A14,, You have to have some sort of issue with the IPC. That Resistance reading should be very close to zero Ohms.

The IGNITION VOLTAGE only comes from ONE source and if you read good on other ignition supplied components, the switch is most likely not the issue.

YES,,, The C5 electrical system will have small fluctuations when loads are added and removed.

BC

 

PM'd you Bill for a bit of clarity. thanks for all the help
Also found a used 2002 cluster for 60$ seller said all gauges were working upon removal, may just pick it up to see if condition changes with new cluster to rule out mine being bad or good.