Wierd electrics

[Robbie693]

Hi,

My Plus 2 has developed an odd electrical problem (how unusual!).

Driving back from Paul Matty this morning the Fuel, Temp, Voltmeter and rev counter died. Also the ignition warning light came on and the indicators stopped working.

I pulled over to see if I could see anything amiss but couldn't so carried on.

Got home and checked the connections to the alternator. After refitting the thin wire I found the gauges worked again until I tried the indicators. The indicators still didn't work and tripped the gauges out again.

Wiggling the alternator wire made them work again so I drove to work, used the indicators on the way and it cut the gauges out again.

Got to work and tried wiggling the wire, now it does nothing and the ignition warning light is out.

I think the car is charging as it still starts ok (I'll find out later if that's still the case)

It points to something to do with the alternator wire obviously, but I can't understand why the indicators have the effect they do.

I don't have the wiring diagram to hand so has anyone got any ideas?

cheers

Robbie

[norfolk boy]

Hi Robbie,
I had a similar problem a few years back, my alternator belt was loose causing the battery to get a lean charge even though the car would start. The volt meter only registered 12volts but should read 13+. With lower volts the indicators will still go but at a slower flash rate, I may be wrong but I think the flasher unit works on a bi mettalic strip and if volts are low the strip doesnt heat so quickly hence the slower flash rate or if really low wont flash at all.
One way of checking the alternator is working is to run the car with headlights on and dip the accelerator and you should notice the lights brighten at higher revs if they dont you could have alternator issues or belt slack.
Si

[neilsjuke]

Check the ignition switch terminals and the terninal bullet blocks from the ign/sw Green/white wires wiggle the key may also make the fault.
Neil

[billwill]

Truly weird effects are usually caused by an earth wire coming loose.

Current flows the wrong way through other things instead.

[rodney]

It would appear that the wire to the alternator may be broken inside the insulation near the connector. I would strip the wire and replace the connector.

If this wire is broken then you will not be charging and the low volts from the battery can cause weird effects due to the voltage stabiliser for the instruments not working correctly.

Rod

[Alex]

Hi Robbie,

The thin wire should have no effect on charging. It normally is only used for the ignition light on the dash. Yours may have been used to connect to the voltage regulator which does power the fuel guage, water temp and rev counter. Can't explain the indicators though, other than they are voltage dependant for the bi-metalic strip...

Good luck,

Alex

[Robbie693]

Thanks for all the suggestions, I haven't had a chance to poke around yet.

When I drive it home last night, the gauges were working from the minute I switched on. I drove all the way not using the indicators to see how long it would last. Gauges worked fine all the way home, about an hours drive, until I got back and tried the indicators - one flash and dead gauges and indicators again..

Another problem cropped up too, when I turn the wipers off they sometimes carry on wiping for a while before eventually stopping when they feel like it!

Paul Matty fitted a new fan belt while they had the car and it feels tight enough, tighter than the old one was and with no shrieking, so I don't think it's slipping..

[Alex]

Maybe your indicators are wrongly fed from the voltage regulator behind the dash! It will only supply a certain amount of current, then shut down or die.

Your wiper motor has a built in switch which opens when in the park position, turning the wipers off. If you remove the connector block on the motor you can access the switch and find the fault.

Alex

[rgh0]

Faulty fuses with bad connections at the end of the fuse wire can also cause weird effects with the fuse working and not working at random as it heats up with current flow.

Try replacing the fuses that feed the affected components with new ones

cheers
Rohan

[Robbie693]

Thanks Rohan - that sounds like the easiest place to start so I'll try that first. What are the fuse ratings?

Thanks Alex - I did wonder about the voltage stabiliser thingy, I had the dash out a while ago so maybe something has come loose.

Cheers

Robbie

[elansprint71]

Faulty fuses with bad connections at the end of the fuse wire can also cause weird effects with the fuse working and not working at random as it heats up with current flow.

Try replacing the fuses that feed the affected components with new ones

cheers
Rohan

...and clean the fuse-holders before you put the new ones in! I've been having strange things happen this week with my son's '92 Mini- cleaned Joe Lucas's clips and everything works fine now.

Cheers,
Pete.

[Robbie693]

Hurrah! Rohan was correct!

The fuse for this circuit was playing up - it was intact and had good continuity on the multimeter but it seems the plating on the ends was breaking up. Clean up with abrasive paper and it now works.

Thanks again to all, esp. Rohan

Robbie