lt35 horn relay

[Dunk]

Can anyone tell me which relay controls the horn on a 1993 LT35 E Diesel and which circuits the other relays operate. Also does anybody know the right kind of oil for the gearbox, I think mine is very low. Dunk:confused:

[kenney]

As far as i remember i dont think there is a horn relay on your vehicle.The horn has 12v ignition supply over fuse 7 a black on yellow wire at the horn,and is activated (earthed ) by the wire black on brown from the horn plate.Use only authorised gearbox oil G50 SAE 75W90:

[Dunk]

Thanks for your reply kenney, good to know the gearbox oil, should I drain it before refilling and how much do I put in? The horn is along running prob that I can't seem to fix and need for mot. The horn unit is fine, the switch and steering column contacts seem clean, the fuse (fuse 9) is fine, but nothing. When I bypass the switch there's no spark or horn, I'm no elecrical expert so can you suggest what could be wrong/what to try next. I hoped that there was a relay cos I couldn't think of anything else. Thanks to anyone who can help

[kenney]

Check first if you have 12v on the black on yellow wire at the horn with the ignition on,if so you need to find the black on brown wire at the steering column were it runs into the combi switch,earth the wire and see if the horn works,if not then there is a break in the black on brown wire to the horn.If the horn works then you have a faulty horn plate or a faulty earth wire to the steering column.It depends on which gearbox you have but around 2.5ltrs should be enough,I think it is fuse 7 for the horn according to the wiring diagram i have.

[Dunk]

OK I've managed to fix it, I had to buy a multimeter-£14, but well worth it. It was something very simple in the end, but I'd been trying to fix it for about a fortnight and it was 'doin my head in'.
I checked the voltage at black with yellow supply to horn and got 12v, and then tried earthing at steering column from brown with black earth return but no result. So now I think there must be a break in brown with black between horn unit and steering column connector. But first I look at voltage at black with yellow again and find it variable, like I kinda did before and try earthing the horn directly from the other terminal- I can't understand why it doesn't sound, 12v supply, directly earthed,this means the horn unit is knackered, but I know it,s ok. Variable voltage at supply is clue- the connections within the heat shrinked spade connectors to the horn are badly corroded, despite me cleaning them from the outside and they seem good there's no circuit. I cut off both spade grips and attached wires directly and the horn went peep peep for the first time in two years!
thanks for you suggestions kenney they were a great help- it is fuse 9, horn and reversing lights