603 - electric windows

[David C]

If you take a look at my sketch below you will see that +12V on all connections is very nearly what you need. It is only the top right connection on the left hand switch in the sketch that provides earth and causes current to flow.

[David C]

If you have +12 volts supplied from the driver's side switch then the circuit for the passenger switch can be simplified as in the attached diagram.

The best tool for fault finding will be a 12V bulb that draws a few amps of current. A digital multimeter may give misleading readings as it won't put any load on the circuit.

[Peter Hoskin]

Sorry for the break in communications, we had a successful BOCA Rally in the Victorian Alps followed by a couple of days in the Snowys.
I received and fitted to the passenger door a new switch, it did not work but did restore to working the drivers switch! progress!
Circuit breakers-in request for replacements I received cut off switches which have a 411 no. but of no use to me but following Kevin' s comments I applied brain and realised my logic was wrong. I assumed that an overcurrent sent the circuit to earth whereas it breaks the circuit to earth. Makes sense.
I attach a sketch of the connections on the new and old switches. The new switch corresponds to the connections shown on David's sketch except my Up and Down appear reversed. I have shown the connections with colour codes, the wiring diagram does not show which is the UP or DOWN end of the switch - can anyone enlighten me? I assumed the BY wire goes to the DOWN end of the Passenger switch?

[David C]

Can you confirm what you now have? It sounds as though the driver's window works as it should. Does the passenger's window operate from either switch?

The switches are symmetrical so, unless they have any markings, they will be fine either way up.

[David C]

Per my post of 22nd March, if all is well on the driver's side you will have 2 x 12V supply and 2 x earth on the passenger switch. Check on the passengers switch with a meter that the 12V doesn't drop to nothing when the switch is operated. If it does then you have a high resistance in the wiring or the driver's door switch.

You can use a sealed beam headlamp bulb with flying leads to test that you have good supply and earths. It will draw about 4 amps which will be enough to show up any high resistance in wiring or switch.

Assuming the feed to the windows is fused you can very briefly test with the breakers bypassed to earth, although I doubt the breakers are at fault unless you have bad enough luck that they have both chosen to fail at the same time.

[Peter Hoskin]

Thanks David for your two responses.
Current situation
Following failure of passenger window to raise or lower from either of the two switches and no problems on Drivers window I changed over the two switches on Drivers side and Drivers window continued to operate correctly so I assume both switches are working correctly.
I fitted a new switch to the passenger side. It failed to work but the Drivers switch now does.
This suggests a failure in the wiring unique to the passenger switch.
At present the car is with my chum investigating the front end replacing bushes etc. At 84 I am finding in increasingly difficult to get under the car and operate heavy tools, or more exactly getting up again so I do the shouting while he does the heavy lifting. It may be a day or so before I am able to continue with this puzzle but I will prepare a test lamp in readyness, currently using a voltmeter and a 2volt test lamp.

[David C]

I suggest testing as follows:

Using sealed beam headlamp with flying leads, remove and test cables on rear of switch on passenger door - both 12V supplies and both earth paths through breakers. If these are all good then that suggests all is well with driver's side switch and cables to passenger side. It will also give an indication that the breakers are working.

If all good then remove middle cables on passenger door switch (motor cables) and very briefly apply 12V in both polarities - ideally from a suitably fused supply. If no movement of the window this will suggest either an unserviceable motor or wires to it or a micro switch that is not passing current - if indeed the 411 has them. The Piper motors on the 410s so equipped have a separate micro switch for each end of travel but I suspect the 411 just kills the path to earth when the motor stalls and the current increases.