MK1 Reverse Light Electrical Issue

[ahetzel]

I have dealer installed reverse lights on my MK1 with an intermittent problem. When I shift into reverse my Tach, Fuel Gauge and Directionals sometimes stop working. The only way to clear the problem is to remove and reinstall one of the fuses. The issues doesn't blow the fuse, it just needs to be taken out and reinserted. Any ideas? I will check to see if I can find a replacement switch for the reverse lights that mount on the trans next to the speedo cable.

 

[Duke Mk1a]

Sounds like a grounding problem. Clean the grounds for the reverse lights and switch on tranny.

 

[trevor91773]

reverse light switch

The switch that activates the reverse lights should have a rubber boot covering it. When shifting into reverse the switch/mount flexes enough at times to touch the frame and ground the circuit thus shorting and blowing the fuse. My personal experience: I paid a transmission shop to change the clutch on my tiger and everything went off without a hitch. A few days later I was running errands and put the car in reverse... and everything except the engine and headlights went dead. It was fine to get home but with some inspection realized the shop never reinstalled the boot. Luckily, after a call, they were able to find it. I reinstalled it. If you do not have one maybe you should wrap the back of it in electrical tape as a temporary fix until a replacement is acquired.

 

[Warren]

2 fuses

Such is the life with only 2 fuses. I had a similar issue and when a 30 amp fuse was installed it took a little time to blow with a intermittent ground of a P.O. installed bulb holder in taillight. Most of the cars you see have mods to add some protection in added items, and you see them scattered about cars along with hidden kill switches.

I agree with the grounding boot issue and the weak ground attachment points and not very clean connections on your fuses. The little papers inside stock fuses are labeled 20 constant 35 peak I think, which seems a lot to have surging about the weak system. Maybe it's just not grounding bad enough to blow the fuse and just over heat the little gauge voltage reducer chinga. I'd change fuses too and see that they added a fuse in the power supply to the switch.

 

[0neoffive]

Electric Nightmares

Some (a lot) of shop time gets spent fixing grounding issues after owners have restored things and painted them up nice & pretty not realizing that paint is a non-conductor and darned good insulator. Powder coating becomes a real enemy to contact needs. Had one issue a few seasons ago where all the restoration body & paint had isolated the main battery grounding bolt. We now weld in a grade 8 nut to solve any potential snags in that area.

 

[ahetzel]

Thanks for all of the help! I am going to pull the switch, clean up the contacts and grounds and check the wiring going back to the lights just to play it safe and will report back.