[mike]

I just wonder if anyone has come across this problem on an early Diablo.

Fuse no 18 on the main board has blown and there is a short to ground somewhere on this circuit. This fuse serves the central locking, fuel flap, and some element of the electronic ignition. With this fuse gone, the fuel pumps dont cut off at start up, [car runs ok]

I have disconnected the motors for the central locking and the fuel flap, but the short to ground is still there.

Any ideas ??

 

[monahan_z]

Test wire for shorts.

Mike past simple visual inspections, the best way to go about this is to pull the fuse, open the fuse box panel, note the wire colors going to it. Switch on the ignition. Find the +12 V pole of the fuse then from the other pole measure resistance to ground. If it is 0 you have a short. Disconnect the same colored wire at fuel pump see if the wire still goes to ground, if not then the other side of te fuel pump etc. Follow the wires as best you can around the car. If it is a transient loose wire rubbing occasionaly againt the frame it will be a real pain to identify!

Good luck.

 

[mike]

Thanks for that. Good to see that you resolved the Carter motor issue, what a pain in the behind !

This circuit is live even with the ignition off and the battery kill switch disconnected. There is a definite short [less than 1 ohm] from the negative side of where the fuse should be to the chassis.

When I put a fuse in, there is a slight sound from the door locking mechanisms, as the fuse blows. I think it is something in the central locking, but do not solve the problem when I disconnect the doors/fuel filler flap.

If there is any way of obtaining some schematics that show wot colour wires go where, then I may be able to make some progress.

 

[monahan_z]

Fuses.

Mike what year is the car. For the two manuals I have, fuse #18 does the mirrors, reverse and Low Tire pressure indicator, in a 99VT.
Fuse #18 does the power windows in a 2001 6L. I have the complete wireing diagram for the 6L. We are talking about the pasanger side kick panel fuse box right?

 

[mike]

Its a 91. The problem fuse is located in the main board in the passenger footwell. The owners manual lists fuse 18 functions as "injection/ignition control unit, door locking and fuel cap opening"

Quite bizarre, but the main sign of the problem, apart from the central locking not working, is that the fuel pumps stay on when the ignition is on [car still runs ok]

 

[monahan_z]

More on Fuse #18

I cannot remember, its a while since I had my 93VT, but does it have a radio control security key. If the door is not locked, I seem to remember if you put the key in the ignition switch and switch the power on, the fuel pump goes on until you press the security button on the key. Even in my 6L something is whining back there if I do the above unless I press the security button either before I put the key in the ignition (when the door was not locked) or when I unlock the door.

 

[mike]

there is an after market alarm, immobiliser fitted, and I'm wondering now if the short could be from this. If i could find out which color wires go where then it would be so much easier to track this one down

Thanks for your help