fuse keeps blowing

fiater · Post by **fiater** » Sat Aug 12, 2006 9:00 am

The 2nd fuse from the left keeps blowing and I lose the guages and turn signals. It doesn't blow when the turn signals are on. The 4-ways and lights still work. A new fuse lasts a few days. The tach was also acting strange so I unhooked the brown wire from the coil, hoping that was the problem. When the fuse blows now, the tach jumps. Also, before the fuse blows the tach sometimes jumps at higher RPM's. I started cleaning and tightening every ground that I can find and looking for loose or cooked connections. My next step is to pull the dash out and check the guages. My car's a '76 and if the guages from my '80 parts car are the same, I'll probably try them.
Any input would be appreciated. thanks

fiater · Post by **fiater** » Mon Aug 14, 2006 7:19 am

I pulled the inst.cluster out and didn't find any cooked connections, so I put the tach, temp, fuel and oil guage from my parts car in. I also unhooked the clock that didn't work right. Everything seemed fine, so I went for a drive. After a few miles, the turn signals started acting strange. After a few flashes, the dash indicator would stop but the signals wuold still flash. About 10 miles later the fuse blew. I replaced it and it blew in a few min. It seems like the problem's worse when the engine's hot on a hot day. The guage read apx. 190 but the fan wasn't on. I jumped the sw. and the fan came on, so it works. The next day I cleaned the ground cable that's under the car, replaced the fuse and ran the engine for a few min. and the fuse didn't blow. I'll go for a drive today and see how long it lasts.

So Cal Mark · Post by **So Cal Mark** » Mon Aug 14, 2006 11:11 am

the troubleshooting guide lists these possibilities for that fuse;
fuse blows when brake pedal depressed
fuse blows when turn signals are turned on
fuse blows when in reverse
fuse blows when in 3rd or 4th gear.
Once you determine what action blows the fuse, it's not too hard to find the cause. Just from experience I'd suggest you get under the car and check the wires to the reverse light switch. They're very close to the flex joint on the driveshaft and can get damaged very easily

fiater · Post by **fiater** » Mon Aug 14, 2006 12:57 pm

Thanks, Mark, for your input. The fuse blows for none of the above. It just blows when I'm driving down the road. It seems to be worse when everything is hot. I'm still looking for anything that's obvious, like cooked wires or shorts.

So Cal Mark · Post by **So Cal Mark** » Mon Aug 14, 2006 3:13 pm

the key then would be 3rd and 4th gear. There is a switch on the side of the trans that acitivates in 3rd and 4th. It switches the electro valve, part of the emission system. The troubleshooting procedure is about 4 pages long for this system. I'll scan it tonight and post for you, but here's what I would do to isolate the system; there is a light blue/white wire from fuse I that feeds the emission system that is controlled in 3rd and 4th. If you disconnect the light blue/white wire at the fuse box, that whole system will be disabled. The car will run fine without that system. Then if the fuse doesn't blow you will at least have determined which system is the culprit

fiater · Post by **fiater** » Mon Aug 14, 2006 9:26 pm

Thanks again Mark,
I may have found the problem, but I won't know for sure for a day or two.
When I was looking at the wires that go to the tranny, I noticed the band that came around the flex disc was sitting loosely above the tranny and a few inches away from the sender that's at the tail of the tranny. Evidently, I either didn't cut the band or I cut it but left it under the car when I replaced the disc last season. I went for a 10 or 12mi. drive tonite, the engine warmed up to 190 the fan came on and the fuse didn't blow! I'm hoping that the band had been working it's way down to the sender and causing the short. I'll also unhook the lt. bl./wh. wire just to be sure. Thanks again, I think we're on the right track. I don't think that I would have looked at the trany if you hadn't mentioned it.

So Cal Mark · Post by **So Cal Mark** » Mon Aug 14, 2006 9:30 pm

the switch at the back of the tranny is the reverse light, but of course it has power when the key is on. Usually the terminals on the switch are exposed where the wires connect, so the band easily could have shorted them. I'd leave the lt blue wire connected for now, so you'll know which circuit was the problem

fiater · Post by **fiater** » Wed Aug 16, 2006 7:30 am

I think that we've solved the problem! I've driven the car apx. 75 mi. since removing the band and the fuse hasn't blown yet. Thanks again Mark, I'm sure that I'd still be looking at the lights and guages if you hadn't suggested the tranny.

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