looking for 300 sleeper cab headlight wiring diagram. Also some advice trying to figure out why no lo beam but rest of lights work properly. No power to headlights in lo beam. When using test light on one of the wires to headlight switch, panel lights go dim and test light doesn't light. Has battery voltage using dmm. Has one white wire and 9 black wires going to it and 10 black and 1 white wire going to combination switch. Trying to figure out what each wire is for, where it goes, what voltage I should see and when I should see voltage at headlight switch connector and combination switch connector, and what, if anything else I am missing to check in that circuit

This isnt lorries

Aye, Volvo 340 as in the car, not the truck. Sorry dude (Although doesn't one of the old schoolers on here drive a 340 truck... Farrell?)

Evoman wrote:This isnt lorries

both are switched by a relay that is on the middle of the tunnel, in a RHD truck to the left side of the cabin next to the glovebox panel, you need to remove a few dashboard panels to get there.

Relays are under the steering column in RHD cars, can be a PITA to find which one is not working though, but it might well be just dirty connections to the fusebox right underneath at the firewall.

pettaw wrote:in RHD cars

Ah come on now Pettaw, have you read the thread? We're talking lorries here!!

Epic! So now I know why lorries keep coming up when I search on the fleabay, along with all the damned Ferrari's. Anyhow, I hope the lorry is better now.

but does the removed relay function properly? it could well be that the relay sticks or is burned stuck due to the foglights having a higher Wattage then standard

It's okay Anjo, tireboy is really Mr Spambot!

hahaha i already was like WTF reading it but since all F-series (except FH) trucks combine the normal beam and foglights via the same relay instead of lighting ECU (for simplifying country-specific lighting rules) the spam-comment read as a true story to me