Technical Pulsating electrics and warning lights?

[Shepherd]

Do we have an auto electrician on board on the forum?

The electrics on my Multipla JTD 2003 have been pulsating quite rapidly in the last couple of months but it's not consistent. Some days it is totally normal and other days like today (very wet day??) when I pushed the brake pedal to activate the brake lights, or used the right indicator, the heater blower was pulsating rapidly at the same pace as the indicators flashing or the brake pedal being pressed then the warning lights on the dash threw a wobbly for about 5 seconds and the car chugged for a couple of seconds but then all went back to perfectly normal (probably after I stopped braking and shut the indicators off). I think the warning lights etc came on because the voltage dropped to a certain level that the main CPU gave the warning.

It is worth noting that for the first half of my journey today (approx 20 min) everything was perfect.

I am thinking along the lines of possibly either a bad earth somewhere or the voltage regulator on the alternator.

Any suggestions would be appreciated.

Thanks

Jim

 

[momoe]

I think your bad earth deduction is pretty much spot on, check the earths from the engine and chassis to the battery first but you may need to check the earths on the
instruments clusters.
Worst case scenario, you might have to run new earth(s) from the cluster to any suitable chassis point.
Also might be worth checking the battery to make sure you're getting over 12 volts with the engine not running and that the battery is charging when the engine is running.

 

[Shepherd]

momoe, thanks for the advice. greatly appreciated.

 

[martyc5674]

Guaranteed bad earths.
The fact it's pulsating in sync with your flashers would lean me towards that area.

I had a poor earth on one of the tail light connectors and it was giving similar results to what your experiencing.

Try this.
Turn on lights and hazards.
Take off the covers to your back lights (local to lights inside boot)
Wiggle the connector blocks and see if your lights start behaving funny (blinking off when flashers come on etc)
You might be lucky and have sane problem ad me..a faulty connector block)

Marty.

 

[Shepherd]

Marty,

Cheers for the info. Very helpful. Were you getting warning lights on the dash?

Thanks
Jim

 

[martyc5674]

No warning light but it was logging a fault.

Just as an aside the problem turned out to be a bent pin inside the connector block... Straightened it up and haven't had the problem since.
I guess it got bent when a previous owner was replacing bulbs or something.
Marty.

 

[Shepherd]

I was told today that it may be a loose connector somewhere?? I know these have been troublesome on quite a few Multipla's.

 

[Shepherd]

Here is an update on the problem so far.

It has now started to switch off at random and it's always associated with the heater blower pulsating or just a massive increase in power from it for a couple of seconds (like going from number 1 to 4 or higher) then all the lights on the dash start flashing (as if the ignition has been switched off for a split second) than back on again. It even cut out at a traffic light today but started easily and away it went for about 5 minutes until the dash lights came on again but this time I was moving. If the car is running it will sort it's self quite quickly and get going again.

The fan pulsating or increasing in power is usually always brought on by switching on one of the lights (indicator, head lights, brake lights etc).

I am thinking about removing the heater blower fuse to see if this stops the fault then if it does that would pinpoint a defective blower motor?

Do you think an auto electrician would be able to pinpoint the fault by plugging their testing device into the cars computer?

Any thoughts or advice would be greatly appreciated.

 

[momoe]

Still sounds like an earth issue to me or possibly a wire shorting out somewhere.

I'd get the multimeter out and start checking resistances at various points, if no obvious anomalies turn up then eliminating equipment by removing fuses isn't a bad next step.

 

[Shepherd]

Thanks to all for your advice. Here is an update for you. A couple of days ago I removed the heater blower fuse to eliminate the circuit, and guess what? the problem has disappeared and I am well chuffed now that I don't need to pay an auto electrician to diagnose the fault. So the fault is either with the heater blower wiring or the heater blower itself. I vouch for the latter. A friend at work told me that it may well be that the pollen filter has let some water/moisture in and the blower has sucked it up and destroyed itself?? Thanks again to all who advised on this. This forum is a lifeline for all of us owners of old, dying and much loved Multiplas. Thanks guys.

 

[Zundapp]

The multi-connector for the heater blower motor gave a bit of trouble on mine.

If you look up under the left/centre of the dash area from the passenger footwell you'll see (I think) a couple of white multi-connectors. One of these is for the fan motor.

Give both a good clean with electrical contact cleaner spray - get it in Maplins - and see if that improves matters.