electrical gremlin?

[Huib]

There is no wire connected to the bottom end of fuse 6. It is connected to the bottom of fuse 7. Fuses 6 and 7 are for the low beams.

The way you phrased it sounds like you thought the loose red wire was connected to fuse 6. This cannot be the case. Could it have been connected to the bottom of 3?

The thick brown wire goes to the cigarette lighter on the circuit diagram dated 29/09/70 that I have in front of me. To the spade connector for the lighter is also attached a red wire going to the relays under the bonnet. Since the circuit diagram is obviously not correct I can't really see what the new situation is. I guess the brown wire would somewhere change into a red wire. Or does your car have a heated rear window?

Anyway, have a look at the two relays on a UK car probably also behind the right head light. There is a red wire going to one of the relays. To the same spade connector is attached another red wire going to the second relay. One of them is probably loose. if not, pull them both and test the fuse.

[Andy Craig]

Hi Huib,

It was just an assumption about the stray red wire. All the others male connectors have spades on them so if it doesn't go to 6 then and everything electrical works I guess it's not important! I'll insulate it and leave it alone.....

The car does have a heated rear window so i'll try disconnecting that and testing the fuse. If that doesn't change things i'll try the relays - you're right again, on this (right hand drive) car they are behind the drivers side headlight. If the relays appear to be ok i'll start tracing the brown wire.

Thanks again,
Andy

[Huib]

OK

My early schematic which is on my disc and the only one around does not show a heated rear window. All other documentation is in my workshop.

I would guess that the brown wire does indeed go to the switch for the heated rear window and that the red wire to the relays branches of from the spade on the switch.

[Andy Craig]

I think we've found the problem : with the red wire which connects the 2 relays disconnected the fuse is OK and the motor will not run. Reconnect the relays and remove the brown wire to fuse 1 and the motor runs.

So I need new relays, yes? Do you think i'll be able to get them from the same place that supplied the capacitor and bush-kit for the alternator? Or are they specialist items (please don't say Omicron.....)?

Andy
p.s - Huib, you're the KING! Thank you so much for your help.

[Huib]

> with the red wire
> which connects the 2 relays disconnected the fuse is OK and
> the motor will not run. Reconnect the relays and remove the
> brown wire to fuse 1 and the motor runs.


This I don't understand. If the fuse is ok., the motor should run

[Andy Craig]

Ah....

Let me run over it again just to make sure :

Both red wires connected to relay and brown wire to fuse 1 = motor runs but fuse pops instantly

Both red wires disconnected and brown wire to fuse 1 = motor will not run but fuse OK

Both red wires connected and brown wire disconnected = motor runs and fuse ok

The neighbours will complain if i go and start the car again now so i'll do the exact same tests again in the morning to be absolutely certain. I may have made a mistake but i'm pretty sure that's how it was.

Andy

[Huib]

I am turning in anyway.
There is something inconsistent.

From the red wires connected to fuse 1 bottom one goes to the coil. So, if you pull those the engine will not run.

I think the red wire going to the relays is connected to the same spade on the switch for the heated rear window where the brown wire is connected. If you cannot get to that easily, you can alternatively disconnect the relays by pulling the red wire from both relays. If everything works OK, you could then reconnect the relays one by one. If you pull the wires from the relays, don't let them touch metal when you jump in the car to turn the switch.

if one o the relays is the culprit, you can open the box and see if there is an internal short.

[Andy Craig]

Good morning Huib!

First of all I missed something last night : there is a red wire connected to the same spade as the brown wire (sorry, it was dark in the garage!).

Secondly with EVERYTHING connected I tried to start the car earlier today..........it ran fine. It ran fine for several minutes and there were no signs of trouble from the fuse (??????????????).

I'm out this afternoon so I'll get back on the car this evening and follow your advice on disconnecting the relays one-by-one and hunting down the heated window switch.

As ever my sincere thanks,

Andy

[Andy Craig]

Hi there,

I got back down to this job last night and noticed that the lowest spade connector on fuse 1 (brown and red wires) had a crack in it and snapped when i tried to push it back into place. I replaced the spade (using the correct crimping tool) and since then I haven't had any trouble and all the cars electrics work!! (??)

I can't honestly see how a cracked spade connector was causing the problems but i've run the car for about 30 minutes since i replaced the spade and it appears to be fine. I'll just have to take it for a short run later and see what happens.

Having used up all the existing fuses trying to fix the short I've had to go and buy a new set. If you could advise me on the correct rating of the fuses I should use it would be safer than me guessing! I think that fuse 1 should be a 16 amp but don't know about the rest.....

Many thanks, especially to Huib,
Andy

[Huib]

Does the claxon work?

Indeed difficult to see how the cracked spade would cause the problem. Be prepared for the problem coming back. I now have a correct circuit diagram on my computer. If you wish I can mail it.

What you call fuse 1 is fuse 9 on the schematic. They start counting at the other end. The fuse ratings are nowhere in the documentation. I think you should be all right with 8 amp fuses but buy a box of 16 amp fuse too. 7 an/or 8 and/or 9 (counting as on the schematic) may need something heavier than 8 amp