electrical prob

electrical prob

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Discussion

Gillyrx

Original Poster:

88 posts

222 months

Monday 29th October 2018
quotequote all
Ok here we go, when you turn ignition off and remove key the batt, handbrake and heater leds remain on but dim? if you apply footbrake or wiper arm the ign light gets brighter and other two go out? Also when you turn ign on the oil light comes on as normal but no batt light. Disconnected fuses, relays and ecu one by one but lights stay on dull? Earth issue maybe. Any advice gratefully received.

Penelope Stopit

11,209 posts

109 months

Monday 29th October 2018
quotequote all
Disconnect the thin warning light wire from the back of the alternator, the colour of the wire may well be Brown/Yellow
The chances are that one of the diodes that are part of the diode trio which puts the battery light out has gone faulty (short circuit)

Gillyrx

Original Poster:

88 posts

222 months

Monday 29th October 2018
quotequote all
mine was yellow, disconnected it from alternator no difference I'm afraid

Penelope Stopit

11,209 posts

109 months

Monday 29th October 2018
quotequote all
With the Yellow disconnected and the ignition keys removed (Warning Light/Lights Glowing), check with a multimeter if there is a voltage between earth and the Yellow cable
Post back here

Are you sure that you have removed all the relays and also that an incorrect relay hasn't been fitted somewhere, water or corrosion in a relay will cause this fault., also water or corrosion in a plug or in the fusebox

Gillyrx

Original Poster:

88 posts

222 months

Monday 29th October 2018
quotequote all
I will check voltage at yellow wire tomorrow and report back, had a good poke about earlier including dash top off, I imagine everyone thinking alternator but I'm not convinced.

Penelope Stopit

11,209 posts

109 months

Monday 29th October 2018
quotequote all
Sorry, you've lost me
I suggested you disconnect the warning light wire from the alternator to prove it was or wasn't the alternator

You having disconnected the alternator proved that the alternator isn't at fault

Nobody here will suggest it's the alternator as you've already proven it's not

Gillyrx

Original Poster:

88 posts

222 months

Monday 29th October 2018
quotequote all
Fair comment. I will check for voltage at disconnected yellow wire tomorrow an let you know.

Penelope Stopit

11,209 posts

109 months

Monday 29th October 2018
quotequote all
Ok, the alternator diode trio going short circuit will give this fault and is the easiest to prove/eliminate before maybe delving deeper

Loach1

431 posts

141 months

Tuesday 30th October 2018
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I had a similar issue on a totally different car (big old Sequoia). All sorts of things would stay on after removing the key, but seemed to be running at very low power. The starter position of the key switch was weird too, starting without turning all the way. I thought it was the trailer wiring, then assumed the alternator.. I had the battery checked, found a dead cell and got a new battery and it’s been perfect ever since.

Gillyrx

Original Poster:

88 posts

222 months

Tuesday 30th October 2018
quotequote all
Ok checked voltage at disconnected yellow batt wire 0 volts, checked voltage at new battery 12.6, started car voltage went up to 14.2. turned ignition off and guess what no dim lights ? Happy fault has gone but bemused at why.

Penelope Stopit

11,209 posts

109 months

Tuesday 30th October 2018
quotequote all
Yellow battery wire?????????????????
I thought there was a Yellow warning light wire

Due to the fault vanishing after disturbing the wiring at the alternator I suggest you ASAP disconnect the battery and check the wiring loom in the area of the alternator and further along. What you have described suggests there could be cables rubbed through and shorting together

Is the thin warning light wire at the alternator yellow?

Gillyrx

Original Poster:

88 posts

222 months

Tuesday 30th October 2018
quotequote all
Yes just to confirm the yellow wire I mentioned is the small battery tell tale wire.

Penelope Stopit

11,209 posts

109 months

Tuesday 30th October 2018
quotequote all
Gillyrx said:
Yes just to confirm the yellow wire I mentioned is the small battery tell tale wire.
OK. With the fault on the car (Keys Out) the thin yellow warning light wire should be showing a voltage that is lower than battery voltage and that same voltage that shouldn't be there is travelling along to the battery warning bulb in the cluster, it then travels through the bulb and down to earth through one or more circuits such as ignition relays or lighting circuits. When you put your foot on the brake that voltage that shouldn't be there travels through the battery bulb, through the brake light switch and down to earth through the 2 x 21 watt brake light bulbs and this is why the bulb illuninates at full brightness when applying the brake

Take a look for rubbing cables, they often firstly rub through at a bracket or other object and then rub/short together, this scenario often takes place close up to the alternator body or where the cables run from the alternator around the engine etc

Gillyrx

Original Poster:

88 posts

222 months

Tuesday 30th October 2018
quotequote all
thanks that makes a lot sense, no fault at the minute but i will investigate wiring as suggested.

Penelope Stopit

11,209 posts

109 months

Tuesday 30th October 2018
quotequote all
Good luck in finding the fault

Gillyrx

Original Poster:

88 posts

222 months

Wednesday 14th November 2018
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Quick update on elec prob. It turned out to be faulty diodes in alternator as suggested. Had unit refurbed and all is good.

Penelope Stopit

11,209 posts

109 months

Wednesday 14th November 2018
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Nicely done

Gillyrx

Original Poster:

88 posts

222 months

Wednesday 14th November 2018
quotequote all
Penelope Stopit said:
Nicely done
Thought I would update as there's nothing worse than following a thread with a similar problem and not finding out the outcome.

Penelope Stopit

11,209 posts

109 months

Wednesday 14th November 2018
quotequote all
Gillyrx said:
Penelope Stopit said:
Nicely done
Thought I would update as there's nothing worse than following a thread with a similar problem and not finding out the outcome.
Yes, this was good thinking on your part, it would certainly help others if everyone gave good feedback