Lamp Wiring

PostPost by: Galwaylotus » Tue Jun 24, 2014 9:46 pm

My S3 SE FHC seems to follow the wiring diagram for the S1 & S2 more than the S3.
My headlamps are not lighting but the flashing function does work (they do flash). I cannot find the headlamp relays on the car. The flasher unit and relay are where they normally are - in the left front wing forward of the radiator but I cannot locate the headlamp relays.
Second problem: my turn signals are not working. It's a bear lying on my back under the steering wheel trying to trace cables!
My instrument lamps don't light either. There is voltage at the switch and out to the red/white cable. That cable then disappears under the dash but I can see where it loops to each instrument. Problem is there's a R/W cable with a bullet connector that isn't currently connected to anything at one end. The other end is in a 4-port connector but the only empty port is the one beside it.

The background is a change to negative earth and conversion to an alternator. When that was first done I had headlamps and turn signals but no ignition warning light and no panel lights. I also replaced the pressure activated brake light switch with a push button switch activated by the pedal. That is working. There is an electric fan in front of the radiator and it along with its indicator lamp work as installed. There's an electric fuel pump in the boot and it works too.

Any suggestions as to how I might trace the problems would be welcomed. Apologies for the long-winded post but I'm getting very frustrated. Thanks in advance.
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PostPost by: normand » Wed Jun 25, 2014 8:32 am

My S3/4 also has S2 wiring with electic window loom added, there is only one headlight relay,behind the dash,it requires an earth from one of the h/l microswitces to operate it once the lights are raised. The live comes from terminal 8 of the main light switch.Blue wire. Hope this helps with one problem.
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PostPost by: robertverhey » Wed Jun 25, 2014 9:00 am

Hi yes my late s3 has an s2 loom modified for door electric window switches. Really made me scratch my head when trying to sort all the spaghetti behind the dash. Once I'd figured this out, it was a lot easier to follow the wiring in the s2 loom diagram in the workshop manual. The s3 loom diagram is all but illegible. You might find it easier to follow s2 loom as well. It's a pretty simple circuit, well it made sense to me, so that means it's pretty basic.

I wonder who's butt got kicked by Mr Chapman in 1967 for over-ordering s2 looms!
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PostPost by: Galwaylotus » Wed Jun 25, 2014 9:22 am

normand wrote:My S3/4 also has S2 wiring with electic window loom added, there is only one headlight relay,behind the dash,it requires an earth from one of the h/l microswitces to operate it once the lights are raised. The live comes from terminal 8 of the main light switch.Blue wire. Hope this helps with one problem.

Thanks. That will help. On which side of the dash is it located, left or right? :?
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PostPost by: normand » Wed Jun 25, 2014 11:26 am

Relay location is near steering column supposed to be in socket screwed to back of dash but mine was just hanging in the loom.
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PostPost by: Galwaylotus » Wed Jun 25, 2014 12:19 pm

My directional indicator flasher unit is there. I didn't see a relay but I'll have another look.
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