More brake light problems
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From: St. Libory
More brake light problems
Well the '69 is shorting out somewhere on the brake light and turn signal circuts. I changed the turn signal switch awhile ago and everything was working but I noticed that I didn't have brake lights or turn signals, so something is up again. I have no corrostion on the lightbulb sockets, and they are grounded good. I kind of know what to do, but I don't really want to do it without a wiring diagram to make things easier. With the key in the on position (truck not running) everything works fine, and no blown fuses. However, if I start the truck and try it, then the fuses blow. I'm not really sure if that would/could/should have any effect on my problem. I do know that with just the key on it shows 12 volts, and running is about 15 volts. Any advice or wiring diagrams are greatly appreciated.
Jake
EDIT - I noticed I was somewhat unclear - I changed the turn signal switch back in Oct or Nov, just recently I have been having troubles. Everything was working until a few weeks ago.
Jake
EDIT - I noticed I was somewhat unclear - I changed the turn signal switch back in Oct or Nov, just recently I have been having troubles. Everything was working until a few weeks ago.
Last edited by jseim44; Jun 27, 2006 at 09:51 PM.
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From: Sun River St. George
The difference between engine off and engine running is about 3V + or _! Do you have a high amperage alternator? I like to add a nice fat ground wire between the engine block and frame, between the engine and cab, between the cab and frame and finally between the bed and frame. After that you might try a bigger fuse (as a test only).
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From: St. Libory
I'm not sure if I have a high amp alt or not. I'd have to check. I thought it was odd for it to be running at 15 volts as my 98 run at no more than 14.5 volts. I've thought about trying bigger fuses to see what happens, but the only higher amp fuses I can find are longer and don't fit. Maybe I'm just not looking in the right places.
Anyway, I want to make sure I have this right. The brake lights run through the emergency flasher, the brake light switch (on the pedal) and the turn signal switch. The turn signals run through the turn signal switch as well as the washer switch. Am I missing something somewhere or do I have this all correct? I think my problem is in the wiring on the way to the back. If I have some time this afternoon I'll take a look at it.
Thanks again
Jake
Anyway, I want to make sure I have this right. The brake lights run through the emergency flasher, the brake light switch (on the pedal) and the turn signal switch. The turn signals run through the turn signal switch as well as the washer switch. Am I missing something somewhere or do I have this all correct? I think my problem is in the wiring on the way to the back. If I have some time this afternoon I'll take a look at it.
Thanks again
Jake
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14+ volts is not an unusual output for an alternator. To isolate the problem, disconnect the 4 prong connector just inside the engine compartment on the drivers side, run through the brake and turn lights and see if the fuse blows. That will at least tell you what end of the truck you need to look at. The likliest culprit is a hot wire rubbing on metal either under the dash or on the frame. However, if it only blows when the engine is running it may not have anything directly to do with the brake lights or turn signal.
Blue Oval has the wiring diagrams, they are definately worth the investment as they show what wires in what connectors - when you know that you can take them part in sequence to track down where the problem is.
Blue Oval has the wiring diagrams, they are definately worth the investment as they show what wires in what connectors - when you know that you can take them part in sequence to track down where the problem is.
Last edited by workingdog; Jun 28, 2006 at 07:59 PM.
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From: St. Libory
Well, I used your tip workingdog and I unplugged it and all was well, so I started following the wires down the frame. I then unplugged the very last set of plugs and ran through everything and nothing changed. I then checked the wires to my tail lights (by ohming them out and visually inspecting them) and they were OK. I put everything back together and so far it's working right. I sat in the shop for about 5 minutes with it running and working the turn signals and brake lights. Right now everything works so I really don't know what the problem was, as I didn't find any bare wires or anything that should cause it to short out.
I'm not really sure what else I could check. Any more ideas are welcome.
Jake
I'm not really sure what else I could check. Any more ideas are welcome.
Jake
