Electrical help PLEASE

Ed Carpenter · 10-14-2007, 08:59 PM

Guys first off I HATE electrical issues. My car last weekend shut off on every run I made.It would quit and then pick back up and quit again. No particular spot. One run in first gear, then second, then second and third. You get the idea. The last run it made it shut off completly. It would not restart. I found the fuses on my switch panel had blown. The ignition switch and electric fan switch fuses were blown.If you replace them and turn on the ignition switch they blow instantly. We checked for loose wires, bad grounds, bad switches, etc. Ive had this problem for 3 races now. Have changed a number of things with no results. Ive been told the only way to find it is to rewire the whole car. That sounds like a fun weekend or longer. Any ideas for me. I have a old style arc switch panel with the fuses in front. I have a MSD 7AL2 witha crank trigger. MSD 3 step also. This problem only seems to surface on runs. In the pits no problem in the water no problem.Thanks.

Ed Carpenter

66 Chevy II

4244 SS/H

castle5 · 10-14-2007, 10:24 PM

if a few blows instantly it sounds like a dead short on hot wire. did you try disconnecting fan motor and see if fuse blows .. look for rubbed thru wire shorting against metal. these can be tough..

Todd Bailey · 10-14-2007, 11:45 PM

Ed,

Like Castle 5 said:Check the ground wire(s).

It almost entails disconnecting EVERYTHING and then reconnecting components one at a time until, hopefully, the fuses blow again so you can pinpoint the problem. Electrical problems will drive you up the wall.

best of luck

Alan Roehrich · 10-14-2007, 11:58 PM

It sounds like you have a bad wire going to either the ignition box or the electric fan, or both. It is also possible you have an intermittent short in either the fan motor or the ignition box. It's next to impossible to diagnose an electrical issue without seeing the vehicle.

Uncrated · 10-15-2007, 08:26 AM

This test will let you know if it is the wiring or the component. Make up a ?test wire? rated for the component load. Then add an in-line fuse holder and install a fuse rated for the component. Disconnect your wiring harness from the component and connect the test wire. Using an alligator clip connect the test wire to battery power.

If the fuse blows, the component has a problem. If the component operates normally, then the problem is elsewhere.

Larry Woodfin

Dave Goob Cook · 10-15-2007, 09:53 AM

Your electric fan should be on a relay if it isn't already.

10-14-2007, 08:59 PM	#1
Ed Carpenter Live Reporter Join Date: May 2006 Location: Dripping Springs, Tx Posts: 2,709 Likes: 186 Liked 520 Times in 132 Posts	Electrical help PLEASE Guys first off I HATE electrical issues. My car last weekend shut off on every run I made.It would quit and then pick back up and quit again. No particular spot. One run in first gear, then second, then second and third. You get the idea. The last run it made it shut off completly. It would not restart. I found the fuses on my switch panel had blown. The ignition switch and electric fan switch fuses were blown.If you replace them and turn on the ignition switch they blow instantly. We checked for loose wires, bad grounds, bad switches, etc. Ive had this problem for 3 races now. Have changed a number of things with no results. Ive been told the only way to find it is to rewire the whole car. That sounds like a fun weekend or longer. Any ideas for me. I have a old style arc switch panel with the fuses in front. I have a MSD 7AL2 witha crank trigger. MSD 3 step also. This problem only seems to surface on runs. In the pits no problem in the water no problem.Thanks. Ed Carpenter 66 Chevy II 4244 SS/H

10-14-2007, 10:24 PM	#2
castle5 Junior Member Join Date: Nov 2005 Location: indiana Posts: 39 Likes: 0 Liked 1 Time in 1 Post	Re: Electrical help PLEASE if a few blows instantly it sounds like a dead short on hot wire. did you try disconnecting fan motor and see if fuse blows .. look for rubbed thru wire shorting against metal. these can be tough..

10-14-2007, 11:45 PM	#3
Todd Bailey Member Join Date: Dec 2003 Location: Houston Posts: 311 Likes: 29 Liked 31 Times in 16 Posts	Re: Electrical help PLEASE Ed, Like Castle 5 said:Check the ground wire(s). It almost entails disconnecting EVERYTHING and then reconnecting components one at a time until, hopefully, the fuses blow again so you can pinpoint the problem. Electrical problems will drive you up the wall. best of luck

10-14-2007, 11:58 PM	#4
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,111 Likes: 1,570 Liked 1,811 Times in 412 Posts	Re: Electrical help PLEASE It sounds like you have a bad wire going to either the ignition box or the electric fan, or both. It is also possible you have an intermittent short in either the fan motor or the ignition box. It's next to impossible to diagnose an electrical issue without seeing the vehicle. __________________ Alan Roehrich 212A G/S

10-15-2007, 08:26 AM	#5
Uncrated Banned Join Date: May 2006 Posts: 170 Likes: 0 Liked 0 Times in 0 Posts	Re: Electrical help PLEASE This test will let you know if it is the wiring or the component. Make up a ?test wire? rated for the component load. Then add an in-line fuse holder and install a fuse rated for the component. Disconnect your wiring harness from the component and connect the test wire. Using an alligator clip connect the test wire to battery power. If the fuse blows, the component has a problem. If the component operates normally, then the problem is elsewhere. Larry Woodfin

10-15-2007, 09:53 AM	#6
Dave Goob Cook Member Join Date: Dec 2006 Location: Indy Posts: 422 Likes: 0 Liked 0 Times in 0 Posts	Re: Electrical help PLEASE Your electric fan should be on a relay if it isn't already.