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Relay for rear fogs GTC

Posted: Mon Mar 28, 2016 5:44 pm
by Peter S
Hi
Can anybody help I've lost power to my rear fogs which I got working 3 months ago![Including removing the live lead from the earth side of one of the lights :!: and disconnecting the earth lead from the warning light from the live feed to the auxillary lights :? ]
Having had a look at Peter's wiring diagram it looks like the power comes from the auxillary light relay [currrently there are no auxillary lights fitted],
other topics seem to suggest this is behind the glove box I have 3 relays there but the colour of the wires are wrong - none are red/green or red/purple is it somewhere else :?: or are the colours different, and any ideas as to why I've lost power if its not the relay as there's no power getting to the switch [headlights & ignition on].

Relay for rear fogs GTC

Posted: Mon Mar 28, 2016 5:49 pm
by scimjim
Wire colours may well be different either changed on late cars or change behind the dash, then change back elsewhere (common on the small sports particularly k series Sabres). The aux light relay should be one of the three behind the glove box though.

Re: Relay for rear fogs GTC

Posted: Mon Mar 28, 2016 6:09 pm
by Roger Pennington
The three relays should (I think all 6-on series are the same) be the so-called "ignition relay", the auxiliary lights relay, and the main beam relay (actually only the outer mains). Maybe you could work backwards and eliminate two of them, based on their wiring colours (or just by pulling them out and testing)?

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 8:43 pm
by guybetts
Resurrecting an old thread...

Please can someone tell me what rating this relay should be?

I've finally got to the reason the fog lights are not working, by changing the relay with a spare. Why I'm asking about the rating, is because the one fitted is rated 40amps continuous, and it looks like it's partly melted :!: although that could just be poor quality - it's a square one, not original round type and not a make I've ever seen before.

Guy

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 8:45 pm
by scimjim
Do you have any of the original round ones? I think they’re all identical.

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 9:05 pm
by guybetts
The only original relay under the dash is the ignition relay, but that has 5 'spades', not 4. The mainbeam relay is 30amps, as are the two I've added as per Roger's wire diagram for relaying the headlamps.

I think 30 amps should be fine for the auxiliary lights, but just asking for a second opinion :)

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 10:26 pm
by AJL Electronics
Two 21W lamps are 42W of course. I=W/E so 3.5A. I think any relay would handle that as would just a switch. That's why Reliant never fitted a relay. Melted terminals are due to high resistance connections caused by corrosion or poor connections.

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 11:07 pm
by scimjim
Not sure why the ignition relay has 5 spades, there’s no reason shown on the wiring diagram?

There’s no relay on the fog lights but as the original thread said, the power comes from the aux lights relay.

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 11:30 pm
by guybetts
AJL Electronics wrote:
Mon Jul 29, 2019 10:26 pm
Two 21W lamps are 42W of course. I=W/E so 3.5A. I think any relay would handle that as would just a switch. That's why Reliant never fitted a relay. Melted terminals are due to high resistance connections caused by corrosion or poor connections.
Andy, there is 2 further bulbs for the front fog lights fed via this relay too.
Still only 7A though 8)
Reliant did fit the relay as original.

Relay for rear fogs GTC

Posted: Mon Jul 29, 2019 11:34 pm
by guybetts
scimjim wrote:
Mon Jul 29, 2019 11:07 pm
Not sure why the ignition relay has 5 spades, there’s no reason shown on the wiring diagram?
Good point Jim. Walkers sent me a replacement which has 5 spades :?

Relay for rear fogs GTC

Posted: Tue Jul 30, 2019 1:35 am
by Roger Pennington
guybetts wrote:
Mon Jul 29, 2019 11:30 pm
AJL Electronics wrote:
Mon Jul 29, 2019 10:26 pm
Two 21W lamps are 42W of course. I=W/E so 3.5A. I think any relay would handle that as would just a switch. That's why Reliant never fitted a relay. Melted terminals are due to high resistance connections caused by corrosion or poor connections.
Andy, there is 2 further bulbs for the front fog lights fed via this relay too.
Still only 7A though 8)
Reliant did fit the relay as original.
Apologies if I'm wrong, but I think there may be some confusion here. Yes, Reliant did fit the relay as original. However, as Andy says, the fog lights (front and rear) are not relayed. This apparent contradiction is due to the fact that what the relay does is it is energised when the sidelights switch on, and then provides a supply of ignition-controlled power. That supply is then used in a totally un-relayed manner, to operate the front and rear aux lights. So the relay controls when the lights are available, rather than actually taking the load off the switch, like a conventional relay.

Relay for rear fogs GTC

Posted: Tue Jul 30, 2019 7:01 am
by guybetts
Thanks Roger.
On that basis, back to my original question - what rating should this relay be considering it has battery supply through the switch and the coil :?

Relay for rear fogs GTC

Posted: Tue Jul 30, 2019 2:50 pm
by Roger Pennington
Well, based on Andy's calc it shouldn't matter much, as I think most of the normal cube relays are at least 30 amp? Mine has been replaced, I can't remember if the new one came from GW or VWP, or AES, it's a normal cube one an seems to be fine (but it was a reasonable supplier, not just the cheapest I could find on fleabay).