Need Electrical Help
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 25
Likes: 0
Need Electrical Help
I have a 1989 Corvette I just bought. When I test the fuses for the instrument panel and the fuel pump, neither one shows any power coming into the fuse (using a test light). Coincidentally (??), these two fuses are right next to each other. All other fuses test properly, and I ruled out a faulty fuse.
Any ideas?
Any ideas?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
You can check the fuse with your ohmeter.
The fuel pump fuse only gets 12v to it when the fuel pump relay is closed or the oil pressure switch is closed. When you first hit crank, the fuel pump comes on for 2 seconds and goes off. If the oil pressure exceeds 4 psi, then the oil pressure switch closes and supplies 12v to the fuel pump fuse. Also, if distributor pulses occur, the ECM closes the fuel pump relay. Engine not running, then you won't see 12v on the fuel pump fuse.
The 3 amp INST fuse only has 12v on it when the parking or headlights are turned on.
The fuel pump fuse only gets 12v to it when the fuel pump relay is closed or the oil pressure switch is closed. When you first hit crank, the fuel pump comes on for 2 seconds and goes off. If the oil pressure exceeds 4 psi, then the oil pressure switch closes and supplies 12v to the fuel pump fuse. Also, if distributor pulses occur, the ECM closes the fuel pump relay. Engine not running, then you won't see 12v on the fuel pump fuse.
The 3 amp INST fuse only has 12v on it when the parking or headlights are turned on.
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 25
Likes: 0
JFB - Thanks! I'm sure you just saved me hours of troubleshooting for nothing. From doing some reading last night, it looks like I can jump the fuel pump relay to get it running and drain the remainder of gas in the tank. With the instrument panel, I will check the fuse with the lights on. However, I'm not getting any lighting on the panel to come on, although I can see the display and know it is functioning. Any ideas how to get the lights working on the instrument panel?
Team Owner
Joined: Jan 2003
Posts: 20,316
Likes: 246
From: Summerland B.C. Canada
There are 4 replaceable lights, just behind the bezel. Maybe all 4 are shot.
You will find this useful
http://members.shaw.ca/dankai/Instru...%20Cluster.pdf
You will find this useful
http://members.shaw.ca/dankai/Instru...%20Cluster.pdf
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Thread Starter
Intermediate
Joined: Mar 2009
Posts: 25
Likes: 0
Awesome Agent 86. thanks for the diagrams. I know when I looked at the car before I purchased it, I noticed the dash lights were flickering on and off. Now I can't get them to come on at all. Rather than all four bulbs being out, I'm thinking maybe a bad ground??
Racer
Joined: Jul 2006
Posts: 315
Likes: 0
There are 4 replaceable lights, just behind the bezel. Maybe all 4 are shot.
You will find this useful http://members.shaw.ca/dankai/Instru...%20Cluster.pdf
You will find this useful
http://members.shaw.ca/dankai/Instru...%20Cluster.pdfI tried the link and its says the file is corrupt. wondering if you still have it on your computer somewhere and can email it to me.
Thanks
Tim
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
Just in case you have not checked the light switch, turn it anticlockwise to brighten and clockwise to dim.
Note there is a light sensor at the top left of your instrument cluster,
if the vette is in a dark garage it will dim the lights.
Outside on a sunny day they will be bright.
Shine a torch at the light sensor to check it works, if it doesn't you may have blown dash lamps or a headlight switch fault.
Note there is a light sensor at the top left of your instrument cluster,
if the vette is in a dark garage it will dim the lights.
Outside on a sunny day they will be bright.
Shine a torch at the light sensor to check it works, if it doesn't you may have blown dash lamps or a headlight switch fault.
Racer
Joined: Jul 2006
Posts: 315
Likes: 0
Just in case you have not checked the light switch, turn it anticlockwise to brighten and clockwise to dim.
Note there is a light sensor at the top left of your instrument cluster,
if the vette is in a dark garage it will dim the lights.
Outside on a sunny day they will be bright.
Shine a torch at the light sensor to check it works, if it doesn't you may have blown dash lamps or a headlight switch fault.
Note there is a light sensor at the top left of your instrument cluster,
if the vette is in a dark garage it will dim the lights.
Outside on a sunny day they will be bright.
Shine a torch at the light sensor to check it works, if it doesn't you may have blown dash lamps or a headlight switch fault.