Intermittent electrical fault

Lellostag

Hello all,

Hoping someone might have a few suggestions on a strange electrical fault that occurred for the first time on Friday last week.

The car is a 2003 Mazda 6 with the 2 litre diesel engine (136bhp).

So here goes, last Friday night my wife picked me up from Dublin airport and we stopped at the airport Topaz to fill up the windscreen washer. When done I closed the bonnet and then the car was completely dead when trying to start it. Lights, dashboard and all that was fine, just the engine was dead, not a click, nothing. A few minutes later it started but died almost immediately again.

We called AA and the man came out to us, he had a thorough look at all the connections, fuses and all that without finding any fault, he also ran some diagnostics, but nothing. The car started a couple of times for him but it died almost instantly again. Anyway, after having looked at everything he could think of he was stumped and pretty much admitted defeat. Then of course the car started and ran just fine! The AA man suspected an immobilizer fault or then perhaps a faulty ignition switch or something along those lines, but impossible to know without some proper diagnosis.

The AA man was as surprised as we were, but we decided to try and drive home and hope for the best as it seemed fine at the moment. We only got out from Topaz when it died completely again, so we pushed it back in to Topaz and arranged with a tow truck to bring us and the car home.

On Saturday I started it again at it ran fine but didn't dare to take it out on the road so we used our little backup car instead.

Today now I tried starting it again and it fired up fine once again, I opened the bonnet to just have a look, all was of course fine. I closed the bonnet and the engine died instantly! I tried the same a few times and four out of five times the engine died when closing the bonnet.

So now I'm kind of thinking it's something to do with the immobilizer, but would anyone have any suggestions as to what and how I should try and possibly locate the fault, and hopefully be able to fix it? Or is this something only a garage could do with their diagnostics tools?

Many thanks in advance for any comments or suggestions!


PS. I'm travelling again from tomorrow morning so apologies if I don't respond more or less immediately.

biko

Usually there is an alarm button that gets pushed down when you close bonnet.
This button will trigger the alarm when you open the bonnet without disarming the alarm.

Try disabling this button and see if you can close bonnet with car running.
You can try disabling it by simply taping it down.

If this works then you can have an auto electrician look at the problem.

Lellostag

biko wrote: »

Usually there is an alarm button that gets pushed down when you close bonnet.
This button will trigger the alarm when you open the bonnet without disarming the alarm.

Try disabling this button and see if you can close bonnet with car running.
You can try disabling it by simply taping it down.

If this works then you can have an auto electrician look at the problem.

Thanks biko! I'll give that a go and see if it helps.

Any idea whereabouts this button would be located?

biko

Nope, but it should be along where the bonnet will touch the engine bay. On my Saab it's at the front, on yours I don't know.

Lellostag

biko wrote: »

Nope, but it should be along where the bonnet will touch the engine bay. On my Saab it's at the front, on yours I don't know.

Thanks again biko, I'll have a look and see if I can find it, can't be that hard I suppose!