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Hey guys, so I have a 1988 c4 corvette manual. When I have the car running the turn signals do not work. Sometimes the indicators will just turn on and shine when I flick the lever but they never blink. I replaced my blinker relay in hopes it would change something but it never did still does the same thing. My digital cluster is old and is having problems as well and I’m about to rebuild it myself. However when try to use my right turn signal the turn signal on the gauge also just shows the light not blinking and holds the green turn signal arrow on the dash. However this does not happen when doing the left turn signal, when I try to use my left turn signal nothing works at all. I was thinking it was my ground wires and I had recently done a transmission replacement when I bought the car(transmission predroped when bought) and I didn’t know where the old groundings went or if it affected anything. These two photos are the grounds and I’m unsure where they good or if they’re bad. I currently also don’t have my exhaust on and was thinking that one of them connected to that. Any help would be appreciated.
I think you are definetley chasing a ground problem. I have an 87 and I can not tell the location of your first pic. G104 is a possibility, I will look to see if G104 is different on an 88 but mine is on the drivers side above the oil pressure sensor on the engine block. Make sure grounds on the frame near the turn signals and horn are clean. They are up front on the frame near the turn signals themselves. There are a lot of possibilities and you should check the bulb socket grounds with an ohmeter to see what you get. Do you have LED lights?? Does the horn sound correct ?? Anything else wrong with the cluster ??
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Last edited by Vets-Vet; Aug 16, 2025 at 09:26 AM.
Behind the Battery on my 87, on the frame, is a ground with a braided cable that is important. That braided cable is part of the 5 or so ground wires bolted to the engine block at G104. That braided cable in your pic does not look healthy. Keep in mind I am familiar with my 87, 88's I believe are slightly different electrically but the schematics and pages you are seeing are from 88 FSM.
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Last edited by Vets-Vet; Aug 16, 2025 at 09:51 AM.
I think you are definetley chasing a ground problem. I have an 87 and I can not tell the location of your first pic. G104 is a possibility, I will look to see if G104 is different on an 88 but mine is on the drivers side above the oil pressure sensor on the engine block. Make sure grounds on the frame near the turn signals and horn are clean. They are up front on the frame near the turn signals themselves. There are a lot of possibilities and you should check the bulb socket grounds with an ohmeter to see what you get. Do you have LED lights?? Does the horn sound correct ?? Anything else wrong with the cluster ??
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Okay so the grounds in the first pick were actually dropped right beside the slave cylinder and bellhousing. That’s where I had them attached to originally. Just to answer all the questions:No LEDs, I don’t believe my horn is working, and the cluster is having issues with the lights not being bright enough. I actually turned on the car the other day and all of a sudden it was all lit up and bright but as soon as I unplugged the battery and re plugged it in it went dim again and I can hardly see anything. I am brand new to working on cars and this is my first car. I don’t know the locations of any more groundings to be honest but I will look around my lights and my battery for the ones you mentioned sometime here soon. I work tomorrow so maybe Monday. I attached a video of me trying my turn signals plus the inbrightened dash board. Brightest I ever got the dash
Behind the Battery on my 87, on the frame, is a ground with a braided cable that is important. That braided cable is part of the 5 or so ground wires bolted to the engine block at G104. That braided cable in your pic does not look healthy. Keep in mind I am familiar with my 87, 88's I believe are slightly different electrically but the schematics and pages you are seeing are from 88 FSM.
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Do you believe I should replace some of my groundings then and see if that will fix it. That braided one doesn’t look very good and I have another question about ground wires. Should I find a new place to put the three groundings or will they be okay together all three on the one bolt. Like I said in my last response this is my first time especially with dealing with this problem and any and all help would be amazing.
You should defininetly clean them to a shine. The braided strap should be replace or at least clean it and add a new one along with the old.
A digital volt meter can fool you. You can do a quick test to find grounds and check voltage but they are so sensitive that a bad ground or low current (not enough current to run the device effects voltage but not on the digital meter) can test good on the meter but can not pass enough current to light a light or run a motor. As long as it is a light you can test them with a bulb like a tail light or turn signal bulb, appx 4 amps. But I would not test grounds that come from the ECM computer with a bulb, they draw to much current. Light sockets are OK. I use an 1157 bulb with wires soldered to it. One side goes to 12vdc on the battery and one side goes to ground on the turn signal socket. Conversly you can test power as well. One side on power at the turn signal socket and the other side to ground. You did say you replaced the flasher stat correct?
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Last edited by Vets-Vet; Aug 21, 2025 at 03:21 AM.
You should defininetly clean them to a shine. The braided strap should be replace or at least clean it and add a new one along with the old.
A digital volt meter can fool you. You can do a quick test to find grounds and check voltage but they are so sensitive that a bad ground or low current (not enough current to run the device effects voltage) can test good on the meter but can not pass enough current to light a light or run a motor. As long as it is a light you can test them with a bulb like a tail light or turn signal bulb, appx 4 amps. But I would not test grounds that come from the ECM computer with a bulb, they draw to much current. Light sockets are OK. I use an 1157 bulb with wires soldered to it. One side goes to 12vdc on the battery and one side goes to ground on the turn signal socket. Conversly you can test power as well. One side on power at the turn signal socket and the other side to ground. You did say you replaced the flasher stat correct?
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okay awesome. Thank you for all the help, I am going to take a look at my g101 and attempt to find the g115 and 16 groundings. I will update you once I find them!
I believe I found them. They look really bad, I’m not sure if that gear thing was attached to the actual ground wire but the they’re separated and are all corroded. Even the screw! Do you know if this is g115 and g116 and if so where do I buy replacement? Right grounding Left grounding
That is a lock washer. Clean them all up with a wire brush or a wire brush on a dremel tool and keep the originals.
According to the description above G116 115 are on the frame behind / near the turn signals.
Thank you so much for the help. I’ll update you soon on what happens when I start it back up but for the rest of the week I’m doing some tidying up and replacements for parts but once I’m done I’ll update you!
Make sure you clean the surface / frame where they attach also. Everything has to be shiny included the grounding point. Once that is done and tightened I usually paint over the entire thing sealing it in. The troubleshooting hints in the bottom pic should be helpful. 8A-203-0 location chart is for a 1990, just keep that in mind.
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Last edited by Vets-Vet; Aug 20, 2025 at 08:03 AM.
Turn signal ground problem
