TheSamba.com :: View topic

Wed Apr 25, 2012 4:28 pm

My left park light shorted out about 2 weeks ago and after the smoke cleared I found the wire going from the back of the switch to the left bulb was fried. I replaced the wire to both left and just in case the right and checked all the grommets to make sure it wasnt rubbing anywhere. Yesterday morning driving along with the park lights on the same happened to with the right bulb. Is there somewhere Im not in the know about that this wire can short on or possibly somewhere in the switch? Until that short 2 weeks ago no part of the factory wiring has ever been touched other than a 12 v conversion. Something a little concerning was none of the fuses blew.

Wed Apr 25, 2012 6:23 pm

No fuses blew because Terminal 57 HAS no fuses. There's a lot of pre-67s out there that have had their front parking light wires replaced as a result.

If the entire wire burnt up, it was at the bulbholder that the short occurred. (if the switch was where the short was, the switch and the big red wires leading to it would have been the ones to start smoking)

Do you actually use the parking lights much? (terminal 57 only should come on with the switch in the middle position)

What kind of condistion are the bulbholders on your headlight buckets in?

-Andy

Wed Apr 25, 2012 6:58 pm

Yea I saw the lights were wired straight from the switch to the bulb but didnt know if it was somehow fused with the headlights, being on the same switch. That theory didnt make sense but I wasnt sure. The wire burnt all the way from the terminal on the switch right to the bulb both times. That is kind of what threw me, usually the burnt spot will end near where it found ground. I will have to take another close look at the bulb sockets and see what is up. I really dont use the park lights that much but Im one of those if its there I want it to work the way its supposed to. Thanks for the help with the fuse info.

Wed Apr 25, 2012 7:48 pm

You're welcome. I like to have them functional as well.

The whole terminal 57 thing was an adaptation for the US market. The more common wiring diagrams show the european "city lights" instead, and the US equipment shown in faded dotted lines. Interestingly, the Euro city lights were run to terminal 58 off of the fusebox. Some people dislike that unfused terminal 57 setup and run them in similar fashion to the fusebox, but then those lights are on all the time the headlights are, and are kind of useless, except for a backup if you burn out a headlight. (however most headlight bulbs have a much longer lifespan than the parking light bulbs)

Some people have no choice but to do that... a lot of replacement switches have a 57 on the bakelite casting but no electrical connections for wires!
(there is a very simple way to generate a 57 signal using a common 4-terminal power supply relay.)

And other people just use an inline fuseholder - one wire to terminal 57 on the switch, and use the fuseholder to connect the two wires going to the lights.
-Andy

Wed Apr 25, 2012 7:58 pm

With your info about it not being fused I was going to check the sockets. If I didnt see something I missed the first time the inline fuse was going to be exactly what I am going to do. Hopefully I find the culprit. Ill leave them disconnected before I wire them into the headlight circuit. In fact Ill probably put the fuse in anyway, thats the way it should have been done.

Wed Apr 25, 2012 8:07 pm

We used to remove the headlights and then pound the inner housing down a couple millimeters to create a dimple around the area where the parking light bulb holder connections make their closest approach to the fender. When driving the headlights would wiggle around a little bit and those connections would short without some extra clearance. That would burn the wires up all the way to the parking lamp holders. Oh, then we would either add an inline fuse holder to that circuit or move it over to the tail light circuit (fused.) That part was already covered though. :)

Thu Apr 26, 2012 12:35 pm

Got it figured out. I took the headlight out this morning and as soon as I looked at it it dawned on me. I should have caught it before. The hot wire was wired to the frame of the bulb socket not the center pin. My guess is someone before me wired them backwards and must have never used the park lights. Both times this happened the lights were on for less than a minute. The frame of the socket must have found a ground and just happened. If I remember right I thought the frames have a little isolator where they mount to the bucket. I will get the isolator and swap the wires. I really liked the bucket clearance idea. I thought for sure I was going to take the headlight out and find a black spot where it shorted to the bucket but it looks good.