High Voltage Draw From Heater Fan

[James Cornell 10]

Now it is getting darker and colder I have the lights/wipers/heater on more often in my 205 GTI 1.9 and I have noticed with most of the electric items switched on the window wipers judder back and forth and struggle to work smoothly. I have also noticed that my engine oil pressure and fuel level gauges "jump" up a little bit with every stroke of the wiper and settle back down when the wipers are off.

 

I assumed that the car was drawing too much for the alternator to handle so I fitted a voltage meter and watched.

 

Car running with no electrics switched on 12.8V-13.0V

 

Heated rear screen - 0.2V

Side Lights - 0.1V

Full lights - 0.2V

Radio - 0.1V

Fan Heater - 0.8V

Window Wiper - 0.8V

 

The fan heater has the biggest impact as when in use it is constantly on and creates such a draw that even when driving the battery is struggling to stay above 12V (not good news)

 

My question was, do these rough drawing values seem normal and it is simply my alternator that needs a service, or should I be looking at the considerable draw from the wiper motor and the fan motor (possibly rebuilding them and replacing the bushes/brushes)?

[Anthony 1,002]

If you're only 12.8-13.0v without electrical load then I'd say that your alternator is on its last legs.

 

Should be more like 14.0-14.5v for a healthy alternator without electrical load.

[Tom Fenton 1,541]

Also check the voltage difference between the battery pos terminal and the large terminal on the alternator itself. There should be 0v difference, but the wiring is 20 years old and often not in great condition.

Also what are the battery terminals like, the originals often are stretched from over tightening now and so less than ideal.

[James Cornell 10]

I thought as much, I will pop it down to my local starter/alternator guy and see when he can recondition it for me.

 

Cheers Anthony!

Thanks Tom

 

I will check this when I get back later

[James Cornell 10]

I have got the alternator back now from Autolect (top bloke from Hinckley with anything electrical) and he said he was amazed it even worked as the bushes/brushed were worn, the ring gear was knackered and the reg want working either!

 

All back on now and I have 14.4V at tickover, so nice to do a preventative job instead of the reactive type I am so used to with the Pug

[Jez G 6 1 Cars]

I have identical symptoms. ... Autolect it is then. Thanks.☺

[James Cornell 10]

I'm considering a rebuild of the heater (using the forum thread here) and if I'm in an doubt about the motor I will take it to autolect