No power to starter.
Thread Starter
7th Gear
Joined: Jul 2010
Posts: 7
Likes: 0
From: Unicoi TN
No power to starter.
I just bought a 1990 C4 that has electrical problems. The instrument panel, fuel pump, and starter will not work. I checked all fusible links and replaced the starter enable relay. Could the ignition switch be bad?
I checked fuse boxes and there is no power to the instr,fp1, and crank a/b. Everything else has power.
I checked fuse boxes and there is no power to the instr,fp1, and crank a/b. Everything else has power.
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I just bought a 1990 C4 that has electrical problems. The instrument panel, fuel pump, and starter will not work. I checked all fusible links and replaced the starter enable relay. Could the ignition switch be bad?
I checked fuse boxes and there is no power to the instr,fp1, and crank a/b. Everything else has power.
I checked fuse boxes and there is no power to the instr,fp1, and crank a/b. Everything else has power.
Corvette Enthusiast
Joined: Oct 2007
Posts: 6,797
Likes: 2,721
From: So. Cal.
2025 C7 of the Year Finalist- Unmodified
2024 C7 of the Year Finalist - Unmodified
2023 C7 of the Year Finalist - Unmodified
Windows and radio only work thru switch.
Seats and locks have power all the time.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Those three items, instrument panel, fuel pump, ECM, get power from the same fusible link that goes to a splice. You need the electrical service manual for your car so you can trace power from the battery to all the devices that aren't getting power. A good way to test for power is to use a 12v lamp which draws current. Voltmeters draw so little current to get a reading, they don't test for low resistance to the point you are testing. Remember that power comes through a firewall connector, to the ignition switch and then to most of the electrical systems in the car. Some ign switched power also goes back through the firewall connector. You need to trace 12v power from the battery through the fuse/fuseable link, through a splice, through the firewall, through the ign sw, to the electrical device or back through the firewall to any engine compartment electrical devices. This is the easiest way to find all your electrical problems, and it won't be particularly easy. Sorry, ....get busy. :o
Thread Starter
7th Gear
Joined: Jul 2010
Posts: 7
Likes: 0
From: Unicoi TN
Those three items, instrument panel, fuel pump, ECM, get power from the same fusible link that goes to a splice. You need the electrical service manual for your car so you can trace power from the battery to all the devices that aren't getting power. A good way to test for power is to use a 12v lamp which draws current. Voltmeters draw so little current to get a reading, they don't test for low resistance to the point you are testing. Remember that power comes through a firewall connector, to the ignition switch and then to most of the electrical systems in the car. Some ign switched power also goes back through the firewall connector. You need to trace 12v power from the battery through the fuse/fuseable link, through a splice, through the firewall, through the ign sw, to the electrical device or back through the firewall to any engine compartment electrical devices. This is the easiest way to find all your electrical problems, and it won't be particularly easy. Sorry, ....get busy. :o
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Thread Starter
7th Gear
Joined: Jul 2010
Posts: 7
Likes: 0
From: Unicoi TN
I do have power to the starter on the main post. I know the brake lights are probably on a different circuit than the starter but they only work when the key is turned on. Does this mean I have power to the ignition switch? The buzzer does not indicate there is a key in the ignition.
Last edited by workinonit; Jul 26, 2010 at 10:37 PM.
Le Mans Master
Joined: Aug 2000
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From: Australia
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
I do have power to the starter on the main post. I know the brake lights are probably on a different circuit than the starter but they only work when the key is turned on. Does this mean I have power to the ignition switch? The buzzer does not indicate there is a key in the ignition.
It will help immensely if you will buy the GM service manuals for your Corvette. The electrical diagnosis manual has circuit diagrams of every electrical circuit and a description of every electrical device along with a diagnosis procedure for devices not working. It also has drawings and descriptions of the location of every electrical device. Working without a manual is exactly like trying to fix your car while blindfolded. BUY THE MANUALS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!
Burning Brakes
Joined: Oct 2009
Posts: 773
Likes: 2
From: Minneapolis MN
My "guess" is ignition switch.So you have power/12 volts at battery cable that is on starter?Just no power/12 volts to signal wire at starter while someone is turning ignition cylinder(need an extra person to verify)?Maybe someone can post a wiring diagram for the OP.Need wiring diagram to make things much easier.Go to library & go to Alldata.com & print out diagram-I do this all the time.
Instructor
Joined: Jul 2010
Posts: 129
Likes: 2
From: Delete Delete
I am working on a similar issue in a 95. FSM is here tomorrow and the rebuilt BCM on Monday I think. There is a purple wire from the solenoid to the starter relay which is behind the drivers knee bolster. There is a yellow wire that is switched by the ignition on the feed side of the relay. The relay itself appears to be a switch ground control from the BCM. Hope this helps
Burning Brakes
Joined: May 2007
Posts: 965
Likes: 13
From: turn 12 at Road America or TX
I do have power to the starter on the main post. I know the brake lights are probably on a different circuit than the starter but they only work when the key is turned on. Does this mean I have power to the ignition switch? The buzzer does not indicate there is a key in the ignition.
Thread Starter
7th Gear
Joined: Jul 2010
Posts: 7
Likes: 0
From: Unicoi TN
There is no alarm system that I know of. I have a Chiltons and a Haynes repair manual. Neither one gives a clear picture of what I am trying to do. What is a good name manual to get that I can make sense of? Also, I measured the Ohms on my key and the multimeter said 4.75. How do I translate that to a key #?
Burning Brakes
Joined: Apr 2009
Posts: 877
Likes: 0
From: Broken Arrow Oklahoma
you need the factory manuals, there are two of them one is specific for electrical.
you tell your key maker the ohms and he gets a key with the same resistance and makes you a key.
you tell your key maker the ohms and he gets a key with the same resistance and makes you a key.
Thread Starter
7th Gear
Joined: Jul 2010
Posts: 7
Likes: 0
From: Unicoi TN
I ordered the factory manuals. I hope they arrive this week. I now have power to the starter and fuel pump by a little creative engineering but the injectors are not pulsing. Sounds like a possible VATS issue. We are going to start with the key/ignition and move forward from there. My question is.... does VATS disable the instrument panel too?