Losing 2v somewhere - Ignition Switch?

[JohnFol]

Afternoon all, I get ~9-10v on rear lights / wiper motor when earthing via a lead directly connected to battery -ve (so that rules out a poor earth). I get 14.1v from alternator so suspect the supply side.

I'm gradually going through the electrics and have replaced battery, replaced main wiring to starter motor / alternator / fuse box, replaced HT leads, replaced coil, refurbished starter and alternator, starter now fired by relay etc. and happy to replace / renew parts as I go along.

Other symptom is firing engine is sometimes sluggish, but sparks up really well when it turns.

I have a week off soon, so want to line up parts. Does this sound like a failing ignition switch?

[peteracs]

Hi John

To confirm it is the light switch etc, I suggest take off the steering cowling and measure the input and output voltages from the switches.

For the lights I have relays for the side/low and high beams and on Eric’s suggestion will be looking to do the same on the wiper motor.

This removes the loading from the switch assembly on the steering wheel.

Peter

[JohnFol]

12.1 in, 10.3 out on Green / black and similar for starter cable...

Looks like the electrical part of the mechanism is non serviceable

[JohnFol]

Just a FYI I found a replacement (new) ignition switch, and have details if anyone is interested

[LanciaDave]

I am interested

[Nigel]

John, old topic, but did you find where your voltage drop was?

I have similar drops [10.4] on 2 fuses #11 and #12, the latter
for wipers and indicators.
I also fitted a new ignition switch but this didn't solve my problem.

Nigel