help with cutting out problem

[the blonde bombshell]

Hi to all at the forum, i have an old K reg passat cl with a strange electrical fault. The car will run ok for a few days then whilst driving, suddenly cut out. when i try to restart, the engine will still turn over, however all ignition electrics go off ie oil light, battery light, no indicators (hazards will still work) I suspected the ignition switch, so i connected a switch in parallel with it, when it cut out again, i flicked the switch but still no dash lights. After about an hour, the dash lights will come back on and the engine will fire up. I also tried pulling relays with ignition switch on, to see if the dash lights would go out and maybe that relay was intermittently faulty, but no luck, the dash lights stayed on. If anyone has had a similar problem or knows what the fault is please let me know as i'm going crazy with this fault.

The blonde bombshell

[carelectrician.co.uk]

Hi there, your passat seems to have a power failure problem to the instrument panel and if it has a factory immobiliser (which is coded through the panel) it s no wonder the car will not run when the fault appears. Check a simple thing like the plug connector on the back of the panel, also check around the fuse box/relay plate for any loose connections (with ignition on) to see if lights cut out. Further to this I will need to know more details about car to look up the wiring diagrams, ie vin number + engine code. Regards, Phil.

[Josteb]

Hi, I had a similar problem only on long journey's or in very hot weather, after driving for a while the ignition / start switch didn't work, after changing the switch and starter motor found the problem to be the immobiliser, an overworked tiny relay inside would overheat and stop the engine from starting untill it had cooled down, this could take some time as the box was hidden under the sound insulation and kept nice and warm.