Turn Signal fuse blows

I need help with my truck, 1994 k1500 z71. Every time I pull a trailer it blows the turn signal fuse. It has blown with different trailers. Blows even when I dont use my turn signals. Where should I start? I've looked over all the wiring I could see underneath the back and everything looks good.

Reply to
William
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Use an ohm meter to look. Sounds like a short to me.

GMC Gremlin

Reply to
GMC Gremlin

Its intermittent. Sometimes I can go all day before it blows. Anyone know what else is connected to that fuse that could blow it? I dont have an electrical diagram yet.

Reply to
William

. . ======= ======= Turn Signal fuse blows Group: alt.autos.4x4.chevy-trucks Date: Tue, Sep 14, 2004, 3:42am (CDT+5) From: snipped-for-privacy@aol.com (William)

I need help with my truck, 1994 k1500 z71. Every time I pull a trailer it blows the turn signal fuse. It has blown with different trailers. Blows even when I dont use my turn signals. Where should I start?

I've looked over all the wiring I could see underneath the back and everything looks good.

======== ========

Sounds like your power feed (current) for the trailer lights is using the turn signal circuit for a ground path. Which would mean to me that the turn signal circuit is the shortest path to ground for whatever reason. Being as you have the symptom only when a trailer is hooked up, and changing trailers hasn't stopped the problem, i would suggest you change the trailer harness connector first because the fuse is only blowing when current is flowing to the trailers, and changing trailers does not eliminate the symptom, which eliminates all circuits BEFORE and AFTER the trailer harness connector as being suspect.

so.....

if the circuit consists of....

trailer truck connecter

the math is saying it'sthe connector, or it's harness.

Likely you jest have a corosion problem makeing for a bad ground circuit, or the wires have been yanked one too many times causing a break inside the insulation of the connector itself, letting a wire or two short.

Later in the thread you asked for circuits that may be in parallel or series with the turn signals. Unless you're haveing symptoms that you didn't mention, that info isn't needed.

Use a test light at the pigtail and isolate the brake,turnsignal,running lights, and revearse light circuits by actuating them. Once you have them identified run continuity tests to ground on the circuits or run voltage drop tests from the circuits to ground. I think what yer gonna find is continuity between one of the other power circuits feeding the trailer lights, and the turnsignal circuit.

or.... do an aperage draw test.... back the truck up to a trailer, fabricate yer self some jumper leads to connect the two harness connectors togeather, hook up yer amp meter to the turnsignal fuse and unplug the wires one at a time till the amperage draw drops, thus isolating the circuit to a particuler wire, then trace the circuit from the trucks connector back through the harness till you locate the short. (i'm betting running lights)

or ..... jest run down and get a new pigtail at the AutoZonedOut store, stick it on, hook up the trailer and go fer a test drive.

v=ir

~:~ MarshMonster ~always remember and never forget, current flows from positive to negative~ ======= =======

Reply to
Marsh Monster

I'd like you to describe how to find a short in a tail lamp or directional signal circuit with an Ohmmeter.

Please,

Al

73 Nova, 454, TH350, 9" Ford
Reply to
Big Al

Okay.

0ohm = short. Thank you.

GMC Gremlin

Reply to
GMC Gremlin

Always remember and never forget, current flows from negative to positive. Electricity is the flow of electrons. Electrons in an atom are negatively charged. "positivity" is best viewed as a lack of "negativity". Similar to "cold" being best described as a "lack of heat".

GMC Gremlin

Reply to
GMC Gremlin

And a normal tail lamp circuit would read what?

Al

Reply to
Big Al

I don't see any real need to remember unless you are designing active devices such as transistors or tubes. The military teaches electron flow but all electrical schools teach current flow. Calculations are all the same.

But for more information lamps don't give off light. They are dark suckers. Rather than try to explain that theory here I did a Google and find there are numerous sites that explain how that works:

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If you stick around those places you learn all kinds of helpful information. For example if you think your battery is dead just turn on your headlamps. If they cast a shadow on the ground the battery is going dead. Another way is to press the horn button. If it makes a sucking sound the battery is going for sure.

Reply to
HRL

Had the same problem with my '88 Silverado years back. Found the problem to be a bad ground connection to my trailer light wiring harness plug. Once I secured the ground wire, didn't have anymore blown fuses. Hopes this helps...

Reply to
Craven Moorehead

IF you were silly enough to check with a bulb still installed, 0ohm. IF you weren't silly enough to see if the positive side of a circuit was grounded, infinite ohms. Would you have been less challenged had I said "multi-meter with continuity check (ohm meter that makes noise)" or if I had said "test light (that stabby-thing)"??

GMC Gremlin

Reply to
GMC Gremlin

I remember my Photonics teacher bringing this up in 12th grade :-)

GMC Gremlin

Reply to
GMC Gremlin

Gee, they didn't teach me that in school. I had a Physics professor who had worked with Millikan measuring the speed of light and he didn't even know about it!! Hmm, that was probably long before you were in the 12th grade.

Reply to
HRL

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