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lights and wipers not working? earthing?

Posted: Fri Apr 15, 2016 9:06 pm
by treefingers
went for a long drive to bristol and back last weekend, the car was ok (except for briefly cutting out in traffic when it got hot for some reason. car started when cooled after 2 mins). wipers and lights worked ok.

then the next morning i drove to work in it and the wipers and the headlights didn't work. fuses all ok. the switches do nothing now except if i pull the headlight flasher. as long as i pull on the flasher stalk i can switch the wipers on..?

it seems like an earthing problem.. where do i start? i've checked and i have continuity between the wiper earth wire and the chassis. i just don't know where to check next.. which earths? all brown earth wires are connected at the fuseboard earthing point, none seem to be disconnected.

maybe there's an earth strap i need to run that i am not running, but that wouldn't explain the sudden change?

Re: lights and wipers not working? earthing?

Posted: Fri Apr 15, 2016 9:16 pm
by treefingers
in addition my (din slot mounted) electrical oil pressure and oil temp gauges have no needle movement, so no power from the sender part of the circuit. (although their backlights work..)

this is what makes me think it is a single ground somewhere..

Re: lights and wipers not working? earthing?

Posted: Sat Apr 16, 2016 10:30 am
by bengould
The sudden change, to me, would suggest a bad contact at an already connected earth rather than a missing one. Do you still have the one that goes from where the original coil was to the head? In mine I'm pretty sure I dont and only use the one that goes from the battery to the chassis and then the gearbox, so not sure how important this one would be without the original engine and associated sensors.

Next to the fusebox there is an earth connection for, I think, most of the internal dash wiring. Check all the spades on this are getting a good connection. It kind of looks like a little crown made from spade connectors. (Edit. Just noticed you've already checked this. I really should read things more carefully)

Ben.

Re: lights and wipers not working? earthing?

Posted: Sat Apr 16, 2016 6:04 pm
by james butler
check x relief relay
bridge connections and see if it works then

Re: lights and wipers not working? earthing?

Posted: Sun Apr 17, 2016 12:44 pm
by treefingers
yes ben i thought it was a bad contact too.

after looking up what the x relief relay does i think this is something to check for sure.. need to have a look at my haynes and see which relay that is

Re: lights and wipers not working? earthing?

Posted: Sun Apr 17, 2016 5:15 pm
by bengould

Re: lights and wipers not working? earthing?

Posted: Sun Apr 17, 2016 6:13 pm
by james butler
andy (aka mac on here) had his pack up last year with the same symptoms.

Re: lights and wipers not working? earthing?

Posted: Sun Apr 17, 2016 9:08 pm
by treefingers
that link is just what I need, thanks ben! the first series fusebox is so much more basic!

looks like the x-relief relay is a no.18 relay, I may have one of those. as I understand the x-relief relay cuts power to the lights and the wipers while the engine is cranking.. this sounds like the culprit. if the relay doesn't work am I right in thinking i should then change the ignition switch? I presume the ignition switch controls this relay?

Re: lights and wipers not working? earthing?

Posted: Mon Apr 18, 2016 10:43 am
by Tim_R
Yes, swap the ignition switch and check what you have connected to where in the live feeds on the fuse box, it sounds like something is drawing more current than the ignition barrel can support.

I got through 2 switches on my car after fitting electric window wiring wrong, the main supply was going through the ignition directly.

Re: lights and wipers not working? earthing?

Posted: Mon Apr 18, 2016 9:52 pm
by treefingers
tried two different 18 relays in the x-relief slot.. no good!!

guess ignition switch it is...

the only thing new i can think of is the stereo which i took a switched live feed from the fusebox, cant see this being the cause though.

Re: lights and wipers not working? earthing?

Posted: Wed Apr 20, 2016 8:50 pm
by Tim_R
I think it was around 6 months between switches on my car after fitting the windows, not an instant thing. If you pull the connector off the ignition switch and use a bit of wire between the thick red supply to the switch and the smaller yellow and black wire, it will power up the X relief relay circuit and confirm the switch has packed up.