Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
OK, a 12v tester will help a lot.
Incidentally, you have an early phase 1, probably with the M2.10.3 engine ECU. That's just useful information for you in case you need it in the future. There's actually quite a lot of difference between early and late phase 1 in terms of their electrics.
Your front fog lamp relay is on the right side of the fuse box. It is the top relay of the four.
What you need to do, is put your finger on the relay and, with the sidelights on, switch on the front fogs. You should be able to feel the relay click.
If you're unsure, the relay immediately below it ( 3rd one up ) is the relay for the low beam headlights and the one below that ( 2nd up ) is for the high beam headlights. So stick your fingers on those, switch on the headlights and switch between high and low beams to get a comparison.
If you get a click, it means the coil supply and fuse are OK.
If you don't get a click you have a fault with the actual relay, the switch or the coil wiring.
If it doesn't click :
Remove the relay and swap it with one of the headlight relays. If it is the relay that is at fault, the fog light relay will now click but you will have lost either your dip or main beams. If the fog relay now clicks, check the fog lights have actually come on.
If it still doesn't click, remove the relay again.
Look at the base of the relay and you'll see some numbers moulded into the plastic : 85, 86, 30, and either two contacts marked 87 ( or maybe 87 and 87a ) or just one marked 87. Identify the holes in the fuse box for the terminals marked 85 & 86. With your 12v tester, either 85 or 86 ( the manual says 86 but it wouldn't be the only error in the manual! ) should have +12v when the sidelights are on. If you do get +12v with the sidelights on, you now need to test the earth. If you don't get +12v on 85 or 86 with the sidelights on, you have a relay coil supply fault. If you do get +12v on 85/86 use your 12v tester again connecting it between 85 & 86 and it should light up with the sidelights on and when the fog light switch is pressed on. If it doesn't light up, you have a faulty switch, earth side cabling or a faulty earth ( the latter is unlikely as it is a common earth for the entire dashboard! ).
Finally, for now, also stick your 12v tester into the 30 and 87 terminal. One of them ( probably 30 ) should have 12v on it. If you don't have 12v on either 30 or 87, you have a supply fault between the battery supply to the fuse box and the relay base via fuse F19. If you don't get 12v at 30/87, remove fuse F19 ( 3rd fuse down on the right column of fuses, just above and to the left of the top ( fog light ) relay. With your tester, look for +12v on on of the terminals of F19.
That series of tests should narrow down the fault.