reverse light switch keeps frying
#1
reverse light switch keeps frying
My 93 pickup keeps frying the reverse light switch. Gone through two switches and I'm not about to buy a third one until I figure this out. The switches last about 2-3 weeks then seem to melt between the terminals. Lights work fine with a jumper wire in the switch plug. I have not left the jumper wire in any longer than one minute, jumper does not seem to get hot. Harness between tail lights and cab look fine. All fuses are good. Bulbs good. Plug is clean. Only other electrical issue with the truck is the vehicle speed sensor does not work but sometimes the speedometer jumps all over the board, rolling or not. I'm not sure if the reverse light switch and the vss issues are related. Going to open up the harness between the Trans and the engine bay on sunday. Any input or ideas would be appreciated. Thanks!
#2
Most likely cause would be a short on the side going to the back-up lights. That harness, at least on my first-gen 4runner, is poorly secured and vibrates against the tranny.
Next likely IMHO contamination from oil and dirt down there.
Next likely IMHO contamination from oil and dirt down there.
#5
In could be "mild"short", some leakage to ground, not enough to blow the fuse, OR overload condition like Robb mentions above - Enough to overload the switch but not enough to blow the fuse.
#7
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#8
Here's a pic of the (melted) switch. Not totaly melted but bubbled plastic out the back.
#9
#10
My 93 pickup keeps frying the reverse light switch. Gone through two switches and I'm not about to buy a third one until I figure this out. The switches last about 2-3 weeks then seem to melt between the terminals. Lights work fine with a jumper wire in the switch plug. I have not left the jumper wire in any longer than one minute, jumper does not seem to get hot. Harness between tail lights and cab look fine. All fuses are good. Bulbs good. Plug is clean. Only other electrical issue with the truck is the vehicle speed sensor does not work but sometimes the speedometer jumps all over the board, rolling or not. I'm not sure if the reverse light switch and the vss issues are related. Going to open up the harness between the Trans and the engine bay on sunday. Any input or ideas would be appreciated. Thanks!
#12
Yes, combination of contaminants, including dust could become conductive like I said above.
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Woslagerj
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10-31-2015 04:41 AM