I've got weird problems with the headlights on the sierra, i have side, dim dipped beam with igniton on and in sidelight position [dim-dip] then when i go to dipped beam [second position on switch] i only get it on the passenger side, i've checked the bulb and it's not that & tried a new one just incase, gone through all the headlight/dim-dip relays and swapped them with others, although whether the other ones is any good or not i don't know.

Now i have a feeling someone experienced the same and found it was the switch???

 

Problem sorted!

Traced the wiring diagram and it's wired through the rear fog relay, which obviously i didn't check, gave this a wiggle and we're up & running!

 

James,
Where is the rear fog relay? I seem to have the same problem but I can't see a rear fog relay on any of the diagrams I have....

CheeRS,
Iain

 

Relay B in the main fuse box under the bonnet.

 

Thanks James,
On my car (3 door) the relays are numbered rather than lettered, the second one, II, is described in the owner's manual as front fog lights. I assume we talking about the same thing; I swapped all the yellow relays round to see if they made a difference but no joy

Identical symptoms though, looks like I'm going to have to do some hard work with the multimeter myself, thanks anyway

CheeRS,
Iain

 

Ah, no sorry, mines a later one on a K plate.. I have both, letters and numbered relays!

 

Can anyone tell me where the bulb failure module is located on a Sierra? I'm still having problems with my dipped beam, the voltages are all over the place andI annot make any sense of it . I'm also seeing an intermittant phantom error for the rear lights and suspect (hope) the bulb failure module is to blame or all this...

CheeRS,
Iain