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Mike S.
Mike S., Classic Car Mechanic
Category: Classic Car
Satisfied Customers: 6803
Experience:  A.S.E. certified with 25+ years experience.
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None of the gauges work in my 88 Corvette 35th anniversary

Customer Question

None of the gauges work in my 88 Corvette 35th anniversary car the speedometer the tag the oil to gas nothing works.The tachometer not tag
Submitted: 1 year ago.
Category: Classic Car
Expert:  Mike S. replied 1 year ago.

Do you have voltage to the instrument cluster?

Customer: replied 1 year ago.
Don't know yet did check all the fuses
Expert:  Mike S. replied 1 year ago.

If so check the ground. I see the ground coming from pin D1 of the instrument cluster. Power to pins C16, and D16 for ignition power from cluster fuse #16, and pin D5 for battery power from LCD fuse #3. I have included the instrument cluster wiring diagram.

Expert:  Mike S. replied 1 year ago.

Here is a diagram showing the layout of the fuse block.

Customer: replied 1 year ago.
Ok I have to ask could the icm cause or there is a little box by computer that is about 2 inches square that I can't find out what is.
Expert:  Mike S. replied 1 year ago.

Are you asking if the ignition control module could cause this?

Did those fuses I mentioned have voltage on both sides of the fuse?

Expert:  Mike S. replied 1 year ago.

I believe it's called an engine control module on this vehicle. not that little box but what you are referring to as the ignition control module. But there is a HEI module, which I believe is inside the distributor.

Expert:  Mike S. replied 1 year ago.

If you hook a hand held tach to the distributor tach terminal does it work?

Customer: replied 1 year ago.
I'm not at the car yet I will check this evening after lunch but will you tell me what that little box is to.and yes I was asking if the computer could cause this.
Expert:  Mike S. replied 1 year ago.

Is the computer you refer to under the dash on the right side?

Customer: replied 1 year ago.
I put a stand alone fuel injection system on it cause whoever had it before me had changed it to carburetor and I didn't want that so.And yes it has a tachometer in it that works
Expert:  Mike S. replied 1 year ago.

I thought you opened this post by saying the tach didn't work?

Customer: replied 1 year ago.
it is and the little box that I don't know what is also is
Expert:  Mike S. replied 1 year ago.

Anyhow, I don't know what that little box is, I don't know if the computer could cause this until after you confirm that those 2 fuses have voltage to and from, the ground is ok and there is power at those pins, then I will try to figure out if the computer could cause this but right now , I doubt it.

Expert:  Mike S. replied 1 year ago.

Perhaps take a photo of that box, write down what wire colors go to and from it and any numbers off of it.

Customer: replied 1 year ago.
None of my gauges work fuel,speed,oil,volt,tach,or anything.
Expert:  Mike S. replied 1 year ago.

Ok, again you say the tach don't work but you just said before that it did.

Customer: replied 1 year ago.
The tach works on the hand held for the self standing fuel injection system only in the car on the dash nothing works
Expert:  Mike S. replied 1 year ago.

ok

Customer: replied 1 year ago.
Can you send me a phone number to text you pictures of the box that I'm asking about.
Expert:  Mike S. replied 1 year ago.

You should be able to post the photo here.

Customer: replied 1 year ago.
I'm trying to I'm not use to this phone
Expert:  Mike S. replied 1 year ago.

Post it online somewhere and then send me the link. like http://imgur.com/

Customer: replied 1 year ago.
Will have to try that tonight when I get home
Expert:  Mike S. replied 1 year ago.

I see it as a DELAYED INTERIOR LIGHT TIMER

Customer: replied 1 year ago.
Ok thanks I thought it might have something to do with gauges
Expert:  Mike S. replied 1 year ago.

You are welcome.

Customer: replied 1 year ago.
I have voltage for dash lights and odometer but nothing else.
Expert:  Mike S. replied 1 year ago.

Go back then and answer those questions, do you have voltage on both sides of them fuses?

To remind you, Power to pins C16, and D16 for ignition power from cluster fuse #16, and pin D5 for battery power from LCD fuse #3.

Customer: replied 1 year ago.
I do have power at the fuses I checked that first and even put new ones in yesterday to be sure.
Expert:  Mike S. replied 1 year ago.

Ok, you could have said that. Now how about the ground?

Expert:  Mike S. replied 1 year ago.

Also, do you have voltage at those pins I mentioned. You have never mentioned this either.

Customer: replied 1 year ago.
No I don't have any voltage
Expert:  Mike S. replied 1 year ago.

To both of those pins? But you have voltage at both sides of those fuses? Well the that is the problem. find a repair the wire/s or run new wire/s.

Customer: replied 1 year ago.
Is there a fuseable link there anywhere and where does the gauges get there ground from
Expert:  Mike S. replied 1 year ago.

What? From those fuses. I thought we have been over this numerous times.

You said you don't have any voltage? Voltage where? To what pins don't you have voltage to?

Yes there is fusible link that feeds that #3 fuse.

Expert:  Mike S. replied 1 year ago.

Fuse #16 is fed from the ignition switch.

Customer: replied 1 year ago.
Ok I meant from the fuse box to the dash.
Expert:  Mike S. replied 1 year ago.

The key has to be on run for fuse #16 and pins C16 and D16.

Expert:  Mike S. replied 1 year ago.

No, the fusible link would be before the fuse box.

Expert:  Mike S. replied 1 year ago.

Let me ask this again,

Do you have voltage to pin C16?

Do you have voltage to pin D16?

Do you have voltage to D5?

Customer: replied 1 year ago.
Okay I checked again and now I do not have power to either side of the fuse
Expert:  Mike S. replied 1 year ago.

Which fuse?

Expert:  Mike S. replied 1 year ago.

If fuse #16, remember the key has to be on run.

Customer: replied 1 year ago.
I don't have anything to tell what the number is ***** the fuse it just says instrument lamps and he was on
Customer: replied 1 year ago.
I ran a jumper wire to it and with car running still none of the gauges would work
Expert:  Mike S. replied 1 year ago.

Didn't you look at that second wiring diagram I gave you that I said shows the fuse box layout?

If not, go back and look at it. The fuses from what I see run from the top left corner down the left column, then move to the right.

So fuse 3 would be the second one down from the top left.

Fuse 16 would be at the top of the forth column with columns going from top to bottom.

Expert:  Mike S. replied 1 year ago.

So which was it?

Expert:  Mike S. replied 1 year ago.

Sorry, 3rd one down, not second.

Expert:  Mike S. replied 1 year ago.

It goes starting from the top left is fuse #1, then #2 is just below it. There are 5 fuses in the first column. Then #6 would be at the top of the 3rd column. #11 at the top of the 3rd column and #16 at the top of the 4th column.

Expert:  Mike S. replied 1 year ago.

If your fuse block doesn't look like that one let me know.

Customer: replied 1 year ago.
No the things that I had like that is number 15
Expert:  Mike S. replied 1 year ago.

What?

Customer: replied 1 year ago.
The views that I didn't have power to was number 15 number 16 has power
Expert:  Mike S. replied 1 year ago.

I'm confused.

What are you talking about.

Expert:  Mike S. replied 1 year ago.

What views?

Didn't have power to what?

Number 15 and 16 what?

Customer: replied 1 year ago.
Sorry didn't proof read my phone I'm speaking into it number 15 did not have power number 16 does have power
Expert:  Mike S. replied 1 year ago.

Fuse #16?

Are you sure the key is on run?

If so, that fuse is fed from the ignition switch and before that, a rust colored fusible link.

Expert:  Mike S. replied 1 year ago.

That fusible link in under the hood over near the brake master cylinder.

Customer: replied 1 year ago.
Okay I will check it
Expert:  Mike S. replied 1 year ago.

Here is a diagram showing the fusible links,

Customer: replied 1 year ago.
All of the fusible link same to have power on both ends of them
Expert:  Mike S. replied 1 year ago.

check in and out of the ignition switch

Expert:  Mike S. replied 1 year ago.

Any news?

Expert:  Mike S. replied 1 year ago.

Did you check in and out of the ignition switch?

Customer: replied 1 year ago.
I did but I don't know if I had the right switch because I don't show fire going in or out if I check the right one
Expert:  Mike S. replied 1 year ago.

The ignition switch, if the ignition lock cylinder is on the steering column, then the ignition switch is usually at the bottom of the steering column, still inside the car, under the dash. let me see if I can find a diagram.

Expert:  Mike S. replied 1 year ago.

Yes, just where I said. Look at this diagram.

Customer: replied 1 year ago.
That's what I thought and the arm runs to it when you turn the key on and off but I can't find any power to it anymore its got a green wire to yellow wires and a tan wire
Expert:  Mike S. replied 1 year ago.

It would be a red wire coming in. Actually just make sure both red wires coming in have voltage. Then with the key on run or switch on run if you pulled the switch off it's the pink wire that goes to fuse #16.

Expert:  Mike S. replied 1 year ago.

Honestly, I don't think it's going to be a bad ignition switch because you would have been complaining about a lot more things. That same pink wire feeds the distributor, so if there was no voltage because of a bad ignition switch the engine wouldn't' run, plus the same ignition switch pin feeds fuses 5, 12, 13, 14 and the very same exact pink wire feeds fuse 16 as well as fuses 17, 18 and 19. So depending o what don't work, it might give us a clue as to where the problem is from that ignition switch and if you look at the wiring diagram you will notice a splice where that one pink wire from the ignition switch splices out to 4 pink wires. So, it is possible that just that one pink wire might be shorted to ground, short circuits or open.

Expert:  Mike S. replied 1 year ago.

is there anything else on this car that don't work? If so, name everything that don't work.

Customer: replied 1 year ago.
No everything else seems to work as far as I can tell
Expert:  Mike S. replied 1 year ago.

Ok, answer me this. With the key on run, do you have voltage to fuses 17, 18 and 19?

Customer: replied 1 year ago.
Expert:  Mike S. replied 1 year ago.

And fuse #16 has no voltage with the key on run?

Then I would remove that fuse box and take a look at the back of it and see what is going on there.

Expert:  Mike S. replied 1 year ago.

So there is no need to worry about the ignition switch anymore since that very same pink wire feeds all of those fuses, 16, 17, 18 and 19.

Expert:  Mike S. replied 1 year ago.

I've heard of spiders getting in there and their webs creating problems like this.

Customer: replied 1 year ago.
Again I have always had on both sides if 16
Expert:  Mike S. replied 1 year ago.

Had what? I know you are texting from a phone but you have to be more specific.

Customer: replied 1 year ago.
I had got confused about15 but that is for light on radio when I ran a jumper wire to it the lights on my radio stayed on even when key was off
Customer: replied 1 year ago.
16 has always had power on both sides of fuse don't know how to make it any clearer than out
Expert:  Mike S. replied 1 year ago.

So you do have voltage to fuse #16?

Do you have voltage at pins C16 and D16 of the instrument cluster, with the key on run?

Customer: replied 1 year ago.
No
Expert:  Mike S. replied 1 year ago.

Ok, then we already went over this a long time ago.

At 1:01pm I said, "To both of those pins? But you have voltage at both sides of those fuses? Well the that is the problem. find a repair the wire/s or run new wire/s."

Expert:  Mike S. replied 1 year ago.

I would still pull that fuse box out and check the back of it, then check for voltage along both pink/black wires from that #16 fuse to those pins C16 and D16 of the instrument cluster, checking for voltage at each connection until you find out what is wrong.

Customer: replied 1 year ago.
Okay I correct myself what I thought was for the dash lights the pink and black wire do have power both of them on pins 16
Expert:  Mike S. replied 1 year ago.

So we back at the beginning, there is voltage to the instrument cluster at pins C16 and D16 Ok, then is there voltage at the other pin, the pin D5 from that LCD fuse #3?

Customer: replied 1 year ago.
I thought that was for the dash lights which do work
Expert:  Mike S. replied 1 year ago.

Ok, check that ground from pin D1 of the instrument cluster

Expert:  Mike S. replied 1 year ago.

Tell me everything ion the instrument cluster that don't work and also tell me what does work, including the illumination.

Expert:  Mike S. replied 1 year ago.

Ok, I get that the instrument cluster light do work.

Customer: replied 1 year ago.
Bryant no ground and nothing works except for the illumination
Customer: replied 1 year ago.
Sorry phone put Bryant in there
Expert:  Mike S. replied 1 year ago.

What do you mean "no ground"?

Expert:  Mike S. replied 1 year ago.

Run a jumper to a good metal ground from that pin d1 and see if them gauges work now.

Customer: replied 1 year ago.
I mean that it doesn't show to have a ground there I ran a ground wire to it though from the battery and nothing worked still
Expert:  Mike S. replied 1 year ago.

Tell me everything ion the instrument cluster that don't work and also tell me what does work

Customer: replied 1 year ago.
I hooked test light to positive side of battery and touched it to the ground pin number1 and it didn't light up so I ran a ground wire from battery to it and it still doesn't work
Expert:  Mike S. replied 1 year ago.

Still what don't work? Tell me everything on the instrument cluster that don't work and also tell me what does work

Customer: replied 1 year ago.
Dash lights work nothing eelse works
Customer: replied 1 year ago.
Odometer works
Customer: replied 1 year ago.
Odometer and dash lights are the only two things that work
Expert:  Mike S. replied 1 year ago.

Ok, what are the things that don't work and be sure to name them all.

Customer: replied 1 year ago.
Fuel gauge don't oil pressure don't range don't average mileage dont coolant temperature don't voltage don't
Customer: replied 1 year ago.
Speedometer and tachometer don't
Customer: replied 1 year ago.
Oil pressure oil temperature Don't
Expert:  Mike S. replied 1 year ago.

What do you mean by 'range"?

Expert:  Mike S. replied 1 year ago.

Also, what do you mean by "average mileage"?

Customer: replied 1 year ago.
Fuel range and average fuel millage
Expert:  Mike S. replied 1 year ago.

Ok, check for voltage at gauges fuse 317.

Expert:  Mike S. replied 1 year ago.

#17, not 317

Expert:  Mike S. replied 1 year ago.

Wait, you just said you did have voltage at 17 didn't you?

Expert:  Mike S. replied 1 year ago.

Ok, at the telltale assembly, check for voltage from that #17 fuse to pin 14 of that telltale assembly. Key on run.

Customer: replied 1 year ago.
Fuel range and average fuel millage dont
Customer: replied 1 year ago.
My phone is dead and I'm tired of messing with it today I will work on it again next weekend when I am home from work
Expert:  Mike S. replied 1 year ago.

Ok, this post will be closed by then.

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