V40 Strange Electrical problem

sanderstead · Post by **sanderstead** » 20 Jan 2010, 13:52

The problem started with the 'door open' indicator lit on the dash although all doors were closed. Then overnight the clock reset itself and 'CODE' appeared on the radio. So, the electric current was lost at some point. I changed the fuse but that made no difference. I also noticed that at times there was no power to the radio (the 'door open' was still lit or vaguely flashing) and the interior lights didn't work.

After driving home this evening, the engine would not switch off, although the key was removed. The only way to stop the engine was to stall it. As the exterior lights were on and the dash lit, I had no option but to disconnect the battery.

Otherwise the car runs perfectly. Any suggestions would be appreciated.

Post by **billofdurham** » 20 Jan 2010, 15:41

Welcome to Matthew's Volvo Site.

Which fuse did you change?

Bill.

sanderstead · Post by **sanderstead** » 21 Jan 2010, 01:49

Thanks Bill.

Fuse number 7 (red). I changed this a few days ago when the Radio was the main problem. I noticed at that time that the interior lights had also failed.

Obviously things have got a lot worse since!

Post by **billofdurham** » 21 Jan 2010, 12:05

Three possibilities come to mind:
1. Battery connections aren't tight enough leading to
2. Alternator diode in the regulator burnt out. This won't necessarily stop the battery charging but could cause a back feed of power to the ignition circuit.
3. Probably most likely - a bad ignition switch.

Bill.

sanderstead · Post by **sanderstead** » 22 Jan 2010, 01:50

Bill, but would the bad ignition switch cause all the other problems such as the interior lights and radio failing?

Post by **billofdurham** » 22 Jan 2010, 12:08

The radio should be ignition controlled. It should only work when the key is in the 'On' or 'Accessories' positions.

The interior lights and the clock aren't ignition controlled but I have seen all sorts of electrical problems caused by a faulty ignition switch.

I was surprised that you had to change fuse 7 as, according to my fuse list, that does not cover the radio. My list shows fuse 9 for the audio system, electric mirrors, windows and aerial.

Have you had the engine running again since this happened?

Bill.

tomsk1000 · Post by **tomsk1000** » 24 Jan 2010, 13:59

This very much seems to be describing a similar problem to one I have experienced with my 1998 V40 over the past few days. My problem started whilst driving off to work, in that my alarm and hazards started to operate. As the car didnt stop I continued to drive, during which time I noticed the radio, glovebox light and interior lights werent working and also that the trip counter and clock had reset. I also noticed the 'door open' light was glimmering but presume this is because the circuit linked to the alarm. Looking back I dont think the alarm deactivating when I pressed the remote, although the doors opened.
The Volvo manual points to fuse F5(engine compartment) was the culprit. However, when I went to change it I found the car operation totally as normal, with the alarm switching on/off and the radio and interior lights working as normal - Therefore fuse ok. However next morning same problems except for the alarm, as this had clearly switched off before the problem represented. Since then I have locked the car maunally, avoiding the associated alarm affects. I have noticed the problem is very intermitant noticing the radio going on and off maybe 3-4 times per minute and slowly getting worse.
Whilst I have no immediate solution I am working on the wiring diagram to pinpoint possible circuitry problems - although I must say the ignition switch is one as already suggested.
Would be very interested if you get to bottom of this.

Post by **billofdurham** » 24 Jan 2010, 15:31

tomsk1000, welcome to Matthew's Volvo Site.

If you do find anything, please let us know.

Bill.