Yet another sodding electrical gremlin.

Yet another sodding electrical gremlin.

Author
Discussion

RickApple

Original Poster:

429 posts

242 months

Sunday 27th March 2005
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I cleaned my engine bay yesterday, scrubbing around with WD40, and when i went for a drive I found i had no lights, front or rear! I was thinking i'd dislodged a connection, a fuse or earth but have checked them and they all seem fine. Could the fusebox have got a little 'moist'? I cant really think of anything else! I'm considering changing it for a blade fuse type anyway, but in the meantime has anyone got any ideas to restore illumination? thanks!

Extra 300 Driver

5,281 posts

253 months

Sunday 27th March 2005
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Do you have any dash lights? If not my thoughts would be the switch. Chect you're getting a supply first then check the switch.

RickApple

Original Poster:

429 posts

242 months

Sunday 27th March 2005
quotequote all
No dash lights, but the other circuits such as the interior lamp work. How do i use a multimeter to check a circuit? Ive got one but am not too clued up on its use!

guru_1071

2,768 posts

241 months

Sunday 27th March 2005
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spend a 130 quid or so and buy a new loom!!!!

RickApple

Original Poster:

429 posts

242 months

Monday 28th March 2005
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I'd love to spend £130! Whether the local grannies would love to be mugged for it however i do not know! If i change the corroded fusebox, does anyone know of a good place where i can get a replacement and new connectors, or is Halfrauds best [doubt it!]? Would i be right in assuming blade type fuses are better? They certainly seem a bit more durable...

dilbert

7,741 posts

238 months

Monday 28th March 2005
quotequote all
RickApple said:
No dash lights, but the other circuits such as the interior lamp work. How do i use a multimeter to check a circuit? Ive got one but am not too clued up on its use!


There are various types of multimeter, if it's expensive you may not need to do anything bar switch it on..... Consult the multimeter manual.

1) Visually check the fuse is sound, and that it's contacts are clean.

2) Using the Ohms or "Continuity" range on your multimeter, "buzz" out the fuse. If you get any kind of bleep it's fine.

3) Set it up, on the next voltage range up from 12V.

4) Switch on the offending appliance.

5) Starting at the offending item, work back through the switch to the fuse. At each test point check the connection between the loom and the component visually. Find a suitable grounding point, and measure the voltage.

6) Eventually when you find the place where a voltage is indicated, the last thing you tested may be at fault.

7) Switch off the offending appliance.

8) Using the Ohms or "Continuity" range on your multimeter, "buzz" out the wiring between the known good point and the previous point.

9) If you find that there is no continuity, in the wire it's self, one way to find the break is to use a pair of dressmaking pins. Ensure that you only push them into a single core, or you could get a bang. Working along the offending wire with the pins you can locate the break in the conductor.

10) It's far more common for a component to fail, rather than the loom.

RickApple

Original Poster:

429 posts

242 months

Monday 28th March 2005
quotequote all
Thanks very much! Ive been told to do that so many times, without knowing exactly how to go about it. I'll have a look tomorrow.

RickApple

Original Poster:

429 posts

242 months

Tuesday 29th March 2005
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Ive just checked the fuses and the headlight switch. Good voltages on both. However, when i was fiddling the sidelights started working. It was intermittent, which suggests to me its an earth point. I checked the earth point however and its fine. Could it be a relay?

dilbert

7,741 posts

238 months

Tuesday 29th March 2005
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Could easily be.

It all depends on the electrical arrangement of your car.

You do have a circuit diagram, don't you?

RickApple

Original Poster:

429 posts

242 months

Tuesday 29th March 2005
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I do, i'm tracing the problem in the Haynes Spaghetti as i type!

miniman

26,319 posts

269 months

Tuesday 29th March 2005
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Which side of the headlight switch was the good voltage - supply side or load side? If load side, the internals of the switch could be breaking up - the switches often get loose and floppy with age.

RickApple

Original Poster:

429 posts

242 months

Wednesday 30th March 2005
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I got a good voltage on the red and brown wires. Nothing on the blue...

miniman

26,319 posts

269 months

Wednesday 30th March 2005
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Pretty sure the blue is the switched feed from the switch down to the lights. Will check HBOL later.

RickApple

Original Poster:

429 posts

242 months

Wednesday 30th March 2005
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thanks!

RickApple

Original Poster:

429 posts

242 months

Thursday 7th April 2005
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Bump.

Now the indicator circuit has packed in. I'm getting a little annoyed now! HHm! Any more ideas? Ive checked connections and earths and fuses, with no luck. I'm sure its something fairly basic [ It was made by BL FFS ]. Problem is knowing what!

Plotloss

67,280 posts

277 months

Thursday 7th April 2005
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The white cable that supplies the fuse box?

Comes in from the ignition switch.

miniman

26,319 posts

269 months

Thursday 7th April 2005
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Could be the flasher unit - notoriously unreliable IIRC...

RickApple

Original Poster:

429 posts

242 months

Thursday 7th April 2005
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Thanks. I'll have a look tonight!


Edit to Say: Ive just had a go at the connectors again, turned out that the ignition white wire connector was very corroded, cleaned it up and everything works again. Thanks a lot for all your help everyone!

>> Edited by RickApple on Thursday 7th April 18:45