Driving/Fog Lights: HELP!

[Guest]

Just a quickie of a problem with my Driving/Fog Lights.

I am reliably informed that my 1979 924 doesn't have Fog Lights at the front, but in fact these are optional Driving Lights, that operate when full beam is switched on, and the relevant switch beneath the ash-tray is also toggled. The sidelights within these units work perfectly; I just don't seem to get any joy when switching the switch with full beam.

Which is/would be the relevant relay to investigate, and where is it located (if it isn't with all the other relays under the glove-box), or is it just some obscure fuse at fault?

All assistance appreciated!

 

[924nutter]

It is either relay 6 top row third from left or relay 4 bottom rpw 2nd from left. You ahve to remember the Haynes is based on a four speed LHD (probably American) spec car so it could be either. In the Haynes it is annotated as the foglight relay, but is in fact wired to actuate with the main beam, and infact takes it signal from the left hand main beam supply.

 

[Guest]

Thanx for that. Have to say things have moved on somewhat since I posted, and I did subsequently find out that they are Driving Lights, not Fog Lights. It would appear also that they were an 'optional extra' and although my Driving/Fog Lights have both halogen and sidelight bulbs, in my particular instance, their relevant relays are missing from the relay/fuseboard.

The relay in question is one of the two in the middle of the top row of relays. In my car both these are missing (hence no driving lights actuated with full beam). What is surprising, however, is that the console-switch is present and when operated, illuminates a blue indicator between the speedo and rev counter.

Long-and-short; I will continue to enjoy my sidelights, without the addition of extra driving lights!

 

[924nutter]

This is all to do with the way the warning lamp is wired. It's never been of great import to me but clearly the warning lamp take its feed from the input signal to the relay. The switch is probably a standard fitment, and whether the car has fogs or mains depends on the whether the feed is taken from the dipped or full beam, and to which country it is being exported to; everyone gets the switch, but different countries get different wiring looms.(imho)

Simply stated, according to the construction and use regs, a fog light must go out when the main beam comes on (also the rear fogs are inhibited at the same time). The reasoning being to avoid the increase in back reflection and consequent reduction in visibilty that would otherwise occur.