Ancient Polo wiring fault - Richard Hall
Car - 1983 VW Polo. Fault - both wipers and heater fan seem to run slowly, especially when first switched on - they then gradually pick up speed. If you switch the wipers on when the heater fan is running full blast, the fan almost stops, then picks up again. Alternator seems to be charging, and battery is OK as well - will start the car even after it has been standing outside for a week or more.

I reckon either the wiper and heater motor have a common feed which is faulty, or a common earth. Right now I can't find my Haynes manual, and it's too cold to go poking round in the hope of finding something - so can anyone suggest a likely specific cause (and location) of the fault?

Richard Hall
Ancient Polo wiring fault - 659FBE
Richard, Almost certainly a high resistance fuse or connection to the fuse serving these two items. If you pull the fuse out, you may well find it discoloured (change it) or the metal in the connecting sockets softened by heat (more difficult to repair properly, but could possibly tranplant from an unused circuit). A certain indication of this problem is heating up of the fuse when these circuits are under load.

Hope the access is reasonable! (ex Lucas CAV).
Ancient Polo wiring fault - M.M

Aren't these two components on adj' fuses 14 & 15, I'm sure they have a common feed from the ign switch.

Try a decent sized "jump" wire to the feed side of either fuse terminal and see if it speeds things up.

Ancient Polo wiring fault - pmh

What year Polo? Some of the wiring changed in 82? when the new 1047? engine replaced the 1100. The first haynes manual covers upto Jan 82 I think. I am pretty sure that there were some transition models that are somewhat hybrid. If u want the wiring diagram from the earlier range let me know ( model variant and year), I will try to look out the manual and scan it for u.

PS if you have the post 82 manual I would like the Ignition switch section of the diagram if possible.

PS I have had a similar problem with complete loss of power feed to wipers and heater. I think that there are 2 ignition switch fed circuits. I have a permanent 'reverse' power feed suitably fused to overcome the problem on daughters car.

The diagnosis of high resistance (corroded) sounds good, probably fuse tags is the first place to look and would explain the variation with time/current .

pmh (was peter)
Ancient Polo wiring fault - GGM JULES
Just put a jump lead to wiper motor body and 'orrible lump of metal on block to prove a poor common earth connection . If no go, check common relay (X-relief relay perhaps? - its got 2small, 2 large male spade terminals.
Ancient Polo wiring fault - Richard Hall
Thanks everyone - I'm going away for a couple of days, but I'll look at it when I get back. PMH - I'm willing to bet that your problem is to do with the relay that GGM Jules mentions - hidden behind the glovebox (assuming your glovebox hasn't fallen off its mountings yet). It's a 4-pin relay just like a standard switching relay for foglights etc, except for some reason it has a few electronic components inside. I swapped mine for a standard relay from Halfords which seems to have worked well. I wonder what the electronics are for? Incidentally, the slow wiper/heater problem was there before I changed the relay - the old one had failed, and someone had jammed a piece of plastic in the contacts to keep it permanently on, which explained why my wipers kept going when I switched off the ignition.

Richard Hall
Ancient Polo wiring fault - pmh

Thanks for advice, took out relay and found the coil open cicuit. Replaced it all ok now! If only I had had the correct wiring diagram I would have found it straight away!

When I opened the can of the relay I found that the wire from the coil to the rivet on the Tag was a dry joint! It had lasted 19 years! I suppose in a true Bangernomics world I should have repaired it, but lazyness triumphed and at 2 pounds something the relay seemed a cheap option.

PS I think I have now cracked all the poor running problems that have plagued this car for 3 years! I have said that before, so I wont go to print until I have seen it run for at least a week

pmh (was peter)

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