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Fuse Blows when Truck is put in Reverse

26752 Views 6 Replies 6 Participants Last post by  fourwd1
I have a 1993 4WD Toyota truck. The fuse that controls the temp, gas, speedometer gauges, oil, brake, check engine lights, and the blower for the fan blows every time I put my truck into reverse. I took the cluster finish panel off to get at the gauges, thinking the short was there. With no gauges plugged in, when I put the truck in reverse, the fuse still blew. I disconnected the electrical wiring to the transmission where it plugs into the transmission and the fuse no longer blows. I cleaned both ends of the transmission plug but that didn't help. I took apart the tail lights thinking a short may be there. Everything is fine with the tail lights.
Does anyone have an idea what might cause this fuse to blow and how I might fix it? I can take it to a mechanic but am fearful that this might be one of those really expensive electrical problems. Or should I just drive it around without the electrical connection plugged into the transmission?
Thanks, Claire
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The "Back Up" lights will be inoperative with the wiring unplugged from the transmission. If you can live with out them you're probably ok. It's a safety issue at night though...

My guess is there is a short to ground somewhere between the transmission switch and the positive supply side of the circuit or just as likely a bad trans switch.
help 4 u

its the backup relay switch on the tranny that does that when it goes out replace relay and you will be back to normal agian.
Thank you both for your answers. On Monday I took the Back up Relay Switch to my mechanic to do an electrical test on it. He told me that it checked out electrically. I decided to buy a new swirch anyway, installed it, and the problem disappeared. Sometimes it is best to go with your intuition.
Similar problem with my 1989 2WD, 22R truck.
Last week I put the truck into reverse(4speed) and bam, no temp,gas gauge, heater blower quits, no reverse lights, no instrument lights(except batter light upon startup).
I live in Alaska and driving in -35 degree weather last week forced to drive with the window down as I was fogging up the windows due to no heater....SUCKED!!!!

Question: Is there a specific fuse I need to change out along when I change out the backup relay switch? Or will everything(hopefully) be back to "normal" when I change the switch?
I looked at all fuses, both near the battery and near the drivers left foot, and all fuses looked good.....non broken.

I have yet to work on this project, but any helpful advice would be greatly appreciated. i.e. where is the backup relay switch? right at the trans? any info to make this "smoother/easier" would be greatly appreciated. I do also have both chilton and haynes books, and plan to look at both...but just thought if anyone who has done this job themselves before might be able to assist with that maybe the books don't???

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does your truck have a trailer wire harness added? some trailer wire makers used the ground wire for a reverse wire, I found this out the hard way
The b/u lights work off of the 15A ENGINE fuse. If that is blown, a lot of things won't be working.
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