On turning the ignition key - nothing. No dash lights,fuel pump prime, locking fob wouldnt work, although was able to unlock car initially as normal.
After waiting/removing and reinserting key several times all came to life and the car started.
The weather was very wet so maybe damp somewhere or switch/relay/fuse on its way out.
Where to start looking though, would it be a good idea to give the under bonnet fuse boxes a good spray with wd40 or something, or could the ignition switch be faulty although after getting home all seems fine now ?

 

It might be the ignition switch, but I would start with cleaning the power and ground connections, of which there are many. A particular problem area is the chassis to engine ground at the back of the bellhousing, and the battery cables themselves should be cleaned. It's not enough to just check that all the connections are tight, cleaning them is required.

 

many thanks...

AndyP

 

Tighten the negative cable at the battery. How old is the battery?

 

I would add the suggestion to have a look at the "false bulkhead" high power terminals near the firewall under the hood and the high power terminals on each fuse box. Then look to the ground straps. Any of these can manifest like your problem.

 

Many thanks chaps, I've checked the battery and cleaned/tightened the terminals, as well as the engine fuse box leads. My local mechanic suggested the ignition switch may be failing but difficult to diagnose as the problem is intermittant.
I hate bloody electrics, prefer something I can belt with a hammer !

 

Attached is an excellent booklet for troubleshooting that was developed by member avt007. It has been a great help in the past for my XJ.

 

Did the interior lights function properly while all this was going on?

 

I must admit I didnt notice the interior lights, but there was no dash lights/horn/headlamps/central locking/radio etc. The clock was ok.
I,ve done some more checks - the battery and cables there seem fine - reading 14v with engine running at battery +ve and all 4 power regulator(?) bolt threads in the trunk. No residual voltage reading from engine to earth so assume engine earth strap ok.
Want to check the false bulkhead leads, assume its located in the box under the tool kit - it has 4 fasteners, does anyone know how to undo these ?


Many thanks
AndyP

 

The bulkhead connector is on the right side -- yes ...under the plastic cover making up the compartment. It's not used in the USA - we don't get the tools or extra bulbs.

Are you talking about the plastic fixers? holding down the cover? I think they turn and come out .. sorry I can't remember what they look like.

If the interior lights -- headlights etc ... are working then the battery and main lines should be providing power to the rest of the car. If the whole car is dead ... the possible problems are greatly reduced.

 

The headlights and as far as I can remember the interior lights were not functioning when the condition occured, it was like there was no power to anything (except the clock).....

 

No! The "false bulkhead connectors" are on the forward portion of a box looking thing next to the latches. They look like a 3/8" tube.

 

What's No??

Now looking at the picture -- it's held on with screws.

 

Has to be a ground problem if there is power at the forward stub of the false bulkhead connector. At DC volts, put one probe on the stub, other on some part of the engine: voltage is? If there is 12 + volts, check the grounds.

 

Well, the bulkhead connector IS 1/2 "under the plastic cover" I suppose.At least on my engines, you see it without removing any cover.

 

You can't get to the other side -- the line from the battery .. without opening cover.

 

Yep, I agree with that!

 

Located the false bulkhead cables, where the brake servo is. I was initially using another picture as reference from the booklet by avt007 kindly uploaded by avern1 which had a large electrical unit near the cables. Anyway, both cable ends read 12.4V (engine off)......
As mentioned earlier I tested the voltage from the engine when running (meter leads on throttle body and shock tower (earth) and there was very little voltage there (16 on the 2000m meter scale whatever that equates to)...

Thanks
AndyP

 

kyle-
"voltage from the engine" where? and "very little voltage there" what is the atecedent to the pronoun "there"

In other words, where the heck are you getting these voltages near zero with the engine running?

It sounds like you have found the problem but lets be sure.

/

 

You will not get 12v everywhere. Many of the sensors are variable. I would stay away from the T-body -- you don't want to be messing with it.

The connection looks fine -- but I would still open it up and to be sure.

If you are getting 12v at the connector -- and nothing is working ,, including the headlights that don't require a key. This should be easy to trace with the electrical diagram.