O/T Car electrical gremlins

Eric in IL · Jan 17, 2014

The wife informed me last evening her 2010 V.W. Jetta had a headlight out. I went for a look-see. I started the car and the messages on the dash concerning bad bulbs lasted about 5 minutes it seemed. I had eight non-working lights on various areas of the body.

After about 90 minutes of troubleshooting, I found the plastic on the brake light fuse partially melted (fuse was still good). The plastic on the fuse holder showed signs heat also. I grabbed a new fuse, smeared the legs with dielectric grease then re-installed. Presto, let there be light !

So here is the question, how can a bad connection on a brake light fuse also effect :

RF low beam
RF high beam
RF turn lamp
RR reverse lamp
LR tail lamp
LR turn lamp
Rear liscense plate lamps

I have always hated chasing electrical failures !! Sorry for the rant.

jimg.allentown · Jan 17, 2014

Lucas electrical system??

ShadetreeRet · Jan 17, 2014

I too, have ranted long and loud(privately) about the same thing. I hate vehicle electrical systems! A lot of professional techs. even have trouble reading vehicle schematics.
But to comment on your question, problems such as yours can occur because of the way everything is wired together. In other words, one circuit feeds off another.Kinda like the domino effect. Or at least in some cases.

Aleuicius · Jan 17, 2014

Find out why the melting? Might be important.

While there may be some wires in commom, it might be that it all passes thru a module in common for the diagnostic on-board computer and arcing or grounds will cause great enough volt or amp changes in the detection elements close together inside that module to indicate problems - even without direct wire connection

Eric in IL · Jan 17, 2014

Pretty sure the heating is telling me, "bad connection" at the fuse socket. I'm sure the dielectric grease is only a band-aid fix. I need to fix the connection issues tomorrow.

Dick2 · Jan 17, 2014

That's why I drive Toyotas. Never had an electrical problem. Did replace a couple light bulbs (upper brake light and backup light) when the Tundra was 9 years old. Camry is 4 years old; no electrical problems with it either.

Eric in IL · Jan 17, 2014

No idea, but I thought Lucas was used on British cars ??

jimg.allentown · Jan 17, 2014

That was really meant in jest {{grin!}}. When I first started driving when I was a young lad, my father provided me with a small british sedan that had constant electrical problems. It was equipped with a Lucas electrical system - later to become known as the "Prince of Darkness" electrical system. The Girling brakes were an adventure as well. You could depend on the pedal ALWAYS going to the floor on the first pump.

notjustair · Jan 17, 2014

Don't get me wrong - I love VW, but they have some weird gremlins. I have 4 VWs and have owned well over 20 of them.

About a month ago I went to start the convertible. No go. The fuel pump wasn't working. Traced it down and there was a little plastic connector that wasn't making contact in the trunk. I had driven the car in the shed a month earlier and shut it off. Seems like there is always something with them.

gab · Jan 17, 2014

If it has those little plastic fuses, cut one in two and use the spade to insert in the fuse holder terminals and see if the drag to remove is the same or if you have a loose one which creates heat.
Gm had a lot of fuse connection troubles in the last 10 or so years.

John730D · Jan 17, 2014

After checking the fuses, I always check the grounds. More problems are caused by bad grounds than any other source.

And melting at the fuse indicates a bad connection. I use dielectric grease on everything.

O/T Car electrical gremlins

Eric in IL

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jimg.allentown

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ShadetreeRet

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Aleuicius

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Eric in IL

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Dick2

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Eric in IL

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jimg.allentown

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notjustair

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gab

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John730D

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