'77 Westy Back Up Switch

[77_Bus_Girl]

I heard the back up switch can get all gummed up and sometimes that is the reason your reverse lights don't work. If I want to pull mine out to clean it up (or possibly replace it, I have a new one...) is there anything I need to be wary of? When I unscrew it will fluid pour out? When I put it back in, how tight do I need to torque it?

[vdubyah73]

Try cleaning all the connections first. Use a solvent and tooth brush on the sender itself. Be careful with your eyes. The fuse holder may be junk as well. You can get in line fuse holders at auto parts stores, hardware stores, and marine stores. Marine stores will probably a better one for under the hood environments.

Good luck with it, Bill

[Sluggo]

Try cleaning all the connections first. Use a solvent and tooth brush on the sender itself. Be careful with your eyes. The fuse holder may be junk as well. You can get in line fuse holders at auto parts stores, hardware stores, and marine stores. Marine stores will probably a better one for under the hood environments.

Good luck with it, Bill

The Autozone by my house has fuse holders that a lot like the original.

[77_Bus_Girl]

I've cleaned the connections, but where is the fuse holder?

[Sluggo]

I've cleaned the connections, but where is the fuse holder?

Trace the wire into the engine compartment. Should be an inline fuse.

[77_Bus_Girl]

Will do, thanks! Although I think I've cleaned up and checked every inline fuse I could spot...
If it does look fine, what's involved in removing and or replacing the switch?

[vdubyah73]

Power for the back up lights comes from the coil.

Bill

[Sluggo]

Power for the back up lights comes from the coil.

Bill

I should have mentioned that. Chances are it's been disconnected though. I don't know why but 75% of the Buses I've come across with no reverse lights just need to plug it in. If you have a black wire coming from the negative (positive #15-edit) side of the coil and then towards the left side the engine that's probably it. Follow it through the rear wall of the engine compartment and out to the tranny. Somewhere along the side of the left battery tray (late buses) or at the fan housing under a clip (early buses), there should be a fuse. Looks like the fuse holder going to the heater fan.

[77_Bus_Girl]

Ah! I do seem to remember a black (long-ish) wire on the left side of things... I'll check!

On another note - what does the coil do? I see it there all fancy and important looking, but... oh, since I'm troubleshooting this alone, will the reverse lights come on without actually turning over the engine? (yes-edit)

[77_Bus_Girl]

Cool! They work now. It was disconnected. I wonder why they did that?

[SlowLane]

It was disconnected. I wonder why they did that?

Sometimes, and it depends on the vehicle, the insulation on the wire leading from the coil to the backup switch gets chafed where it goes through the firewall. It may ground out intermittently on the sheet metal, causing no end of hair-pulling on the part of the hapless owner, who can't figure out why his temperamental VW doesn't start or dies at whim.

VW Girl, the coil is what makes the spark that ignites the fire. In my opinion, the most understandable diagram of how this works is in Muir's Idiot book (apologies to Colin if he's made his own drawing. I don't recall seeing one). If you don't have one, get one. It's worth having just for the illustrations, even if much of the advice is dated or suspect.

A hardened or missing firewall grommet tends to be the culprit here, or a misrouted wire passed between the engine seal and body sheet metal. Many years ago I helped a fellow figure out what was happening with his Beetle. It would start up fine and run perfectly until he put it in reverse. The wire from the backup switch to the backup lights was grounding to the frame, thereby shorting out the coil only when the car was put in reverse.

[77_Bus_Girl]

A hardened or missing firewall grommet tends to be the culprit here, or a misrouted wire passed between the engine seal and body sheet metal.

Hmm.. interesting. Makes sense I guess - I'll take a look at it tomorrow and see what condition the wire was in at that point. I did drive him around a bit tonight and tried out my "new" back up lights (and hazards!) and all seems healthy! VWs are temperamental - you never know tomorrow!

[chitwnvw]

I have the inline fuse holder but no fuse.

Anyone know what fuse I need?

[Sluggo]

The red 16 amp fuses.

[Amskeptic]

I have never understood why VW would call for a 16 amp fuse for the reverse lights. So I use an 8.
The heater blower inline fuse nearby, I use a 16.
Colin