low beam fuse keeps blowing

explosion242 · 09-20-2004, 02:26 PM

I keep blowing my low left beam fuse. I think it is blowing when I turn off my lights (put them down). Is it a wire that is not grounded? Any ideas?

strath44 · strath44's Garage

That kept happening to me then the whole switch unit burnt out and melted - think it was an accumulaition of dirt/dust over 20 years got a replacement and it hasn't happened since. Unfortunately the switch is really very easily serviced so would tend to have a spare handy - mine went in the middle of night picking someone up at the airport and they stuck up had to drive home on full beam as dipped's weren't working!

mbwilser · 09-20-2004, 06:56 PM

Check the wiring harness where it is attached to the headlight bucket. Quite often the movement of the headlight rotating up and down chafes the insulation. Strip the jacket on the harness so that you can repair the damage insulation with electrical tape.
I had this prob. a few months ago and it can be obvious if someone gives you a clue. It was for me after the clue.
good luck w/ the prob.
MW

adrian jaye · 09-21-2004, 01:03 AM

you are of course using the correct value fuse ?

explosion242 · 09-21-2004, 01:25 AM

Yes, I am using the correct fuses (7.5). I guess I'll take out the headlight and see if there is any problem with the wire.

Thanks

adrian jaye · 09-21-2004, 08:57 AM

hi explosion,
ok, its just an easy mistake to make,

anyway would "I" would do, is

1> check all wiring, if you have and know how to use a digital meter, check for shorts

2> remove the relays which look after the lights and motors, clean all contact and replace

3> lubricate and remove/check the headlight units

4> if its only happening on ONE side, swap the bulbs from left to right or right to left

HTH

A

TSNAPCRACKLEPOP · TSNAPCRACKLEPOP's Garage

i just did this repair,

just checked the continuity in the headlight plug to the round connection, it was o.k. MINE IS A US MODEK 1987 N/A)stripped back the wire in the plug for the lamp and the wire UNDER THE FUSE BOX by unscrewing the two corner nuts and pulling the fuse panel up and tilting it to get under it., (the left low beam is yellow with a brown tracer stripe, the right is plain yellow, and ran a new wire to the light plug . Low beam is the center prong on the headlight.
YOU CAN FIND THE CORRECT WIRE JUST BELOW THE PROPER FUSE NUMBER #23 fuse is the passengers dipped beam. yours may be #21, check the inside of the fuse box cover. its the blown one!lol.

I replaced the wire because it was a quicker repair than going thru the harness and looking for the short.

good luck!! dr tom

TSNAPCRACKLEPOP · TSNAPCRACKLEPOP's Garage

be sure to cut the new wire about 18 inches longer than you think you need to, to allow for tying it up and out of the way.

zip ties, electrical tape,

difficulty level, 2 beers.

explosion242 · 10-02-2004, 05:01 PM

Well I have been busy here lately, but I still have this problem. I have realized that the fuse will blow if I have my radio on. No problem till I power up the radio. Now I bought this car off someone else and I have the receipt of the stereo install by a pro. I have had the car for almost 2 years and just started to have this problem! There must be some kind of short happening when the stereo is turned on but I don't know why it would blow that fuse?

Any ideas?

Thanks in advance!

TSNAPCRACKLEPOP · TSNAPCRACKLEPOP's Garage

if it is a large amplifier setup, i guess it might blow a 15 amp fuse, but most stereos draw very little. does it blow immediately,
does the stereo work?
do the rear speakers have their own internal amp, like mine do? with an individual power line which could short out?
did you check the stereo power line to see where they spliced it in?
do you have a meter to determine continuity, volts, and amps?

later

tom

explosion242 · 10-04-2004, 10:23 AM

Well, I got it fixed! One of the fuses for the radio had a 15 fuse in it(it should have had a 7.5 in it). Once I discovered that I switched it and it seems to be working. I'm not sure why that would effect it, but it did.

Thanks anyway!

TSNAPCRACKLEPOP · TSNAPCRACKLEPOP's Garage

another one rides the bus.......

explosion242 · 10-07-2004, 08:56 PM

What would happen if you had a fuse in that was bigger than what was supposed to be in. Do you risk damaging whatever is getting power to it? Just wondering.

TSNAPCRACKLEPOP · TSNAPCRACKLEPOP's Garage

if the fuse does not blow, the wiring harness will melt, or catch fire, just like shorting the battery terminals across a wire would do. first you smell smoke, or "something burning, then its too late when the insulation melts, and the wires fuse all the circuits into one.

explosion242 · 10-08-2004, 08:38 AM

Ouch!!!

gtroth · 10-10-2004, 03:33 PM

Quote:

Well, I got it fixed! One of the fuses for the radio had a 15 fuse in it(it should have had a 7.5 in it). Once I discovered that I switched it and it seems to be working. I'm not sure why that would effect it, but it did.

Well that doesn't make any sense at all. Sometimes the wiping action of removing and reinstalling a fuse will cut through some corrosion and lower its contact resistance - maybe your 15A fuse was dropping some voltage across it. But even that doesn't make sense. Nice puzzle.