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914World.com _ 914World Garage _ Right head light blowing fuses

Posted by: JFG Oct 12 2017, 01:59 PM

I had a problem whereby the light bucket would not rise but would lower after manually winding it up. I used a check from pelican parts to jump between 87 & 30 in the relay socket (without the relay fitted)

This should jump the motor into a constant raise / lower mode in order to check the motor. It worked the motor perfectly. However when I now refit the relay it blows fuse 12 (16 amp) straight away.

This never happened before and yes I removed the jumper wire first.

Any help with this?

Posted by: BillC Oct 13 2017, 07:11 AM

Here's a simple test for the relay -- Swap over the relay from the left side and see if the right headlight works properly. If the headlight works correctly, you have a bad relay. Otherwise, it's something else, but at least you've eliminated one variable.

Also, trace the wiring harness from the headlight back to the fuse block and make sure there is no damage to it. You could have a short somewhere.

Posted by: jim_hoyland Oct 13 2017, 08:02 AM

I just went through a similiar problem; turned out an external diode on the outer side of the HL Motor had broken and was shorting. Not easy to see at first; you have to poke around. Plus the diode is loosely covered by a black covering.
Some peeps have soldered the diode back; I replaced the Motor with one I got from Bruce Stone.

See Andy thread with pictures of the problem:

http://www.914world.com/bbs2/index.php?showtopic=263805&hl=

Posted by: jim_hoyland Oct 13 2017, 11:07 AM

Picture of the area mentioned above; I didn't discover the issue until I turned on the lights and moved my finger in theat area. The light would momentarily go up or down when the connection resumed

IPB Image

Posted by: JFG Oct 13 2017, 01:01 PM

Thanks for advice. After 3 more blown fuses I figured it was the relay. Strange though as it didn't blow before. Luckily I don't use all relays on the engine board so nabbed one off there and all things work as they should.

Posted by: jim_hoyland Oct 13 2017, 03:50 PM

QUOTE(JFG @ Oct 13 2017, 12:01 PM) *

Thanks for advice. After 3 more blown fuses I figured it was the relay. Strange though as it didn't blow before. Luckily I don't use all relays on the engine board so nabbed one off there and all things work as they should.


Was it the relay in the front trunk ? Never had one of those go south.... sad.gif

Posted by: 76-914 Oct 13 2017, 04:26 PM

QUOTE(jim_hoyland @ Oct 13 2017, 07:02 AM) *

I just went through a similiar problem; turned out an external diode on the outer side of the HL Motor had broken and was shorting. Not easy to see at first; you have to poke around. Plus the diode is loosely covered by a black covering.
Some peeps have soldered the diode back; I replaced the Motor with one I got from Bruce Stone.

See Andy thread with pictures of the problem:

http://www.914world.com/bbs2/index.php?showtopic=263805&hl=

That's a damned good tip, Jim. Now if only I can remember that when and if the time comes. beerchug.gif

Posted by: JFG Oct 14 2017, 01:47 AM

QUOTE(jim_hoyland @ Oct 13 2017, 10:50 PM) *

QUOTE(JFG @ Oct 13 2017, 12:01 PM) *

Thanks for advice. After 3 more blown fuses I figured it was the relay. Strange though as it didn't blow before. Luckily I don't use all relays on the engine board so nabbed one off there and all things work as they should.


Was it the relay in the front trunk ? Never had one of those go south.... sad.gif


Yes. I opened the faulty relay but to be honest i'm not sure what i'm looking at to diagnose a fault.

Posted by: jim_hoyland Oct 14 2017, 05:03 AM

I test them using a 9 volt battery and either an ohm meter (OM)

1st attach the battery to the 85 and 86 pins; you should hear a click indicating the opening of the circuit between 30 and 87

2nd, attach the OM to 30 and 87; there should be continuity until you disconnect the 30 or 87

You can do this with the relay cover off too....

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