Hello all
I have a 95 C4 with just over 30,000 miles. The issue that i am having is i have a good battery and power to everything fuel pump, reverse lights, radio and headlights ect but i have no power to my dash or the starter.
I have check all the fuses in the engine bay and the one panel on the passenger side of the car and cleaned all the grounds. But it still wont start and the interior light wont come on when the door is opened.
Any help would be great.

 

Sounds like an issue with no power to the CCM or with your security system. You might also check Connector C2 at your ignition switch. What is your security light doing?

 

Also check the fuzes and terminals next to the battery.

But what is probably the problem is that the battery cable terminal under the plastic boot is all dirty. Peel-back the red and black boots and look at the cable to plate connection....if white with corrosion.....replace the entire cable.

Let us know whaf you find.

 

I had the same issue with a non runner I bought last summer. Based on the new battery in the car and the charger / jump start unit setting beside the car I think the prev owner may have but the jumper cables on it backwards. I sent the CCM to a couple people to have it rebuilt but only after it went to Georgia and had a few parts replaced was it actually repaired. Get a FSM and check the power into CCM and the grounds. Do a search on BCM and CCM there is a very good pictoral on how to get it to it (not a lot of fun). PS - Take the seat out ---- It is much easier that way

 

Thanks for all the info, I'll give it a try and see what happens.

 

So an update.
I wasn't able to figure anything out so i took the Corvette to the stealership.
What they are telling me is that *ALL* my computers are fried because none of them are communicating with eachother, or something like that. So they want to start replacing the CCM, PCM, ABS, and HVAC one by one to get it running. Now how is it that all these computers are fried but the heat and a/c work as well as the lights, radio, and fuel pump ect?

 

That diagnose is scary from a stealership, get your car back before they do any further damange and either work with us on the forum or find a qualified vette tech in your area. Your talking serious serious $$$ if they go that route! I've been on this forum for over 10 years and this is the first time ever that I've seen someone say that all the electronic modules are fried...that doesn't happen!

 

That's what i'm thinking also. I'm trying to find people who know about Corvette's specifically around my area but no luck so far.

 

Sounds like the problem I had exactly. Turned out to be a bad fuse inside the passenger side door on that little bank of fuses labeled "lcd" something I can't remember exactly. Replaced it and presto, back to normal! looks like you checked that already but try swapping it with another "good" fuse and see if there is any change?

 

That is a poor answer from a dealer. It would be better if they said they are were fried but the way you put it is they did not know and were going to replace one by one till they got it going.

I have seen multable modules fried at one time for different reasons. That being said I would doubt if the ABS or HVAC units would cause the car from starting (dont hold me to that, it would take a little research).

 

yeah it sounds like there going to try and poke prod and spend my money untill they get it right.

 

I have to wonder if someone at the dealership wants to buy your car. Especially if they can convince you it will take thousands to fix it. OR..... Maybe they don't want to work on it. If you can follow instructions and use a volt / ohm meter I would suggest you buy a FSM and follow the instructions. If you get an offer to sell from the dealership let me know --- I think I would do better

 

None of the computers supply power to the dash. The start enable relay will prevent the starter motor from cranking if it isn't closed either by not detecting the correct ign key pellet resistance or a defective clutch safety switch (gear selector switch if automatic) or a defective start enable relay or the CCM (computer). You need to do some diagnostics on the VATS circuit. I'd work on that first. You need to do some diagnostics on the power to the dash. Buy a GM electrical diagnosis service manual for your year and follow the diagnosis steps.
The dealer clearly doesn't know what they are doing, get your car back from them.

 

Look for a burnt out or defective inline wiring fusible link.

Check all ground connection points too.

Only possible ways that all Electronic modules are fried in your car if someone tried jump starting your Corvette and accidentally connected the donor jump 12 volt source backwards.............

Instead of parallel 12 volts with Your Vettes battery-12vdc,
They connected in series.........24 volts dead shorted together at 1,400+ peak amps then let go of the jumper pack or jumper cables.
That creates a huge transient/back EMF/ High voltage with large amounts of current present back to all the vehicles electrical system and sensitive electronics.

I have seen that happen a few times before over my 20 + years turning wrenches for a living.
Leaves an owner like you screwed.

An alternator with a defective voltage regulator that does not limit current flow to the rotating electromagnetic field when needed will cause output alternator voltage to climb above 15 VDC and to over 120 VDC at High alternator rotor RPM's above 4,000.

I have seen that happen Twice.
Rare occurrence but can happen.

Very few Veteran mechanics left in GM garages with any electrical or real electronic knowledge.
Remove and replace is the order in place everywhere.
Unless you find guys like myself in person.

There are a few of us real mechanics left.
Some are here on C4 with You & Me.

Brian

 

If the dealership mechanics get paid flat rate time,
You get 1 hour only for all electrical diagnostic repairs to pinpoint exactly what is wrong.

That is all they ever gave me for paid time troubleshooting electrical & electronics.

Repairs were seat of the pants call(estimated time) depending upon difficulty by my own discretion.

Needless to say all GM mechanics hate electrical repairs other than myself.

They could not make money $$.......flat rate on electrical repairs.

I have a strong background in electronics and service writers and fellow mechanics knew this.

All impossible to diagnose problems were dumped on me.
And everyday.

I still see them in the non GM private shop I work in now.

Does not bother me the least bit tough problems.

Brian

 

They don't want your car in the shop period. lacking a Tech1a or tech II with the proper cartridges for your C4 I wuld get a set of plugs sold by many of the big vendors that will 99% of all the Aldl data from all the computers in the car connected to the ALDL port. While you don't really care about the ABS status or heater controls what you do care about is if the module is alive and communicating. Every one that is alive and sending codes that all is ok is one to cross off the list to narrow down your search and focus on the one that is either no alive or sending errors. Personally I would not even consider buying a C4 without them with me.
Dave

 

For a complex problem like this call Gordon Killebrews C4 help line. It might cost you $60 (might cost you 10) but its money well spent but have all your facts together before you call.

 

RUN Forrest, RUN!!!!

 

In your initial post you stated the interior lights would not come on with the door open... Do your interior lights work from the light switch?

If the 95 chassis is wired anywhere close to my 91, (which I suspect it is), the common points for all these systems are the G106 ground, the fusible links at the jump start junction block and the ignition switch connector C2 per my FSM Electrical Supplement.

When you get the car back, (and yes, get it out of that dealership), recheck the G106 ground (the gang ground on the bellhousing) for broken grounds. If ok, pull the lcd and ctsy fuses out of the fuse panel and check for 12 volts at the fuse block. Then pull the ccm, gauges and clstr fuses and with key on (in run) check for power (12v) at the fuse block. If no power to the last 3 fuses with key on, then go to the ignition switch, connector C2, and check for power at pins A and C.

 

As of right now i'm giving them one chance to get this figured out. I have a pcm on order for the car and if that doesn't work or tell them anything i'm getting it out of the shop. My bill for the dealer is already to much for nothing being fixed.

Brian (87 vette 81 big girl) where do you live? can i convince you to come over for a weekend....... I'll fill your stomach with lots of fresh food!!!

Thanks everyone for your help, i will keep you up to date.