Head scratcher for you

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ulm4lyf

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Trevor
Truck Year
1978
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Sierra Grande 15
Engine Size
350
My turn signal works fine until I turn on my head lights. When I turn them on, weird things happen. The left turn signal no longer blinks, and in addition to that stepping on the brake pedal not only activates the brake lights, but also activates the front side marker and turn signal lights. I did not visually see any obvious bad spots in the wires anywhere, but I don't really know where to start after that. I know how to wire things up to make them work, but I haven't a clue on how to track down wiring gremlins. I do have a multimeter and a test light, but don't really know what to do with either of them.
 

SirRobyn0

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My turn signal works fine until I turn on my head lights. When I turn them on, weird things happen. The left turn signal no longer blinks, and in addition to that stepping on the brake pedal not only activates the brake lights, but also activates the front side marker and turn signal lights. I did not visually see any obvious bad spots in the wires anywhere, but I don't really know where to start after that. I know how to wire things up to make them work, but I haven't a clue on how to track down wiring gremlins. I do have a multimeter and a test light, but don't really know what to do with either of them.
This is not a head scratcher for me, but only because I have seen this sort of behavior before. This is bad ground. Check the turn signals, running lights front and rear. What happens is electricity will find the path of least resistance and if that happens to be backwards though a circuit so be it. Also turning on the headlight (more importantly the running lights) Increases the amount of electricity looking for a ground path. We see this all the time in trailers. If the sockets all look ok look for the ground connections for the sockets. You are likely to find the problem either in a bad socket or more likely a bad ground or bad broken ground wire. Other folks here can probably tell you better the exact location of those ground connections, but you could follow the wires.
 

DoubleDingo

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I'll be tracking these down soon. No night driving until I get it fixed. Luckily the brake lights work when the pedal is pressed. I have replacement bulbs for each socket, and each ground will get unplugged, or unbolted, cleaned, sanded, wire brushed, etc, and then hopefully everything works again. May even add some grounds to make the existing grounds even better. Did that on Crusty Biscuit and there were no issues with those lights, and they shined brighter afterwards.
 

ulm4lyf

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Trevor
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Sierra Grande 15
Engine Size
350
Apparently I'm a huge *******. The whole issue was caused because I put the wrong bulb in the reverse socket and it was grounding out.
 
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Newcman1

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Tulsa
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Bill
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Chevy K10
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I'm wondering how you discovered the wrong bulb was installed. Seems like some thorough troubleshooting to find something like that
 

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