1994 940 no backlit dash lights, but high beam marker on etc

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 06:39

Greetings everyone. It's been awhile since I've been on this forum but I've searched out this problem the last few nights for answers. Here is the trouble. All worked fine up to a couple of days ago. My backlit dash lights and the lights behind my heater controls went out but I still have the lights for the radio. Also, the high beam indicator is on steady as is the left turn signal and fog light indicator come on and stay on when I turn on the headlights. The gas gauge is not working either as it says empty all the time. My power seats work though. I've checked voltage at battery and alternator with the car off and with it running with lights on and the charger is normal. I cleaned the battery posts as well as the positive & negative wires and the ground at the alternator. I do not know the shape of the fuel sender but I'm thinking that this is all an electrical issue somewhere that I've not been able to locate. Any suggestions would be appreciated.

Thank you

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 06:47

Oh, one more item that is happening that I forgot to list. the left turn signal is flashing rapidly instead of it's normal flashing speed as if one of the turn signal bulbs is burnt out but they are all on and working perfectly, it's just a rapid blink. Should I be looking for another ground somewhere to clean?

Thanks again.

Post by **jimmy57** » 16 Jan 2014, 08:24

Pull the cluster and inspect for loose connectors.
Are you sure the turn signal bulbs on that side are full bright?
Bad ground or bad socket can cause fast flash with bulb still flashing but not normal brightness.

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 08:44

I thought about pulling dash out but I was hoping that there was another ground inside the car that I should check first. I believe that the blinker lights are fully lit but I will have to confirm that once it gets dark out. I'm wondering if there is a bulb that's shorting out would cause the backlit dash lights to not work. All of these symptoms happened at the same time except the gas gauge which seems to work when it wants to but nonetheless it could be related.

Post by **jimmy57** » 16 Jan 2014, 09:11

the backlight illumination is controlled by the module that is on backside on lower left. If it fails the radio lights go back to full daytime light level while others are not working.

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 09:20

ahhh, this could possibly be the culprit. If this control module is going bad would it intermittently work fine or would it die all at once? I pulled the blinker bulbs out of their sockets and they are all clean with no signs of them shorting out but the front blinker does appear dimmer than the rear blinker. I will replace bulb to see if that helps any.

Do you know if the high beam indicator, left turn signal & fog light indicator (which come on steady once headlights are turned on) are part of that control module? I will pull part off and post back.

thanks,

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 10:33

So I pulled out the instrument cluster but could not identify the control module. I tried looking for the part online in hopes of getting an idea of what to look for and no luck. Could it be a problem with the dimmer switch? I'm still thinking that there is a ground wire somewhere that is giving me these issues. Do you know where the earth grounds are inside the car? I've got someone coming over to look at purchasing this Volvo so I would like to be as honest and up front with what the problem could be.

Thanks,

cgreygoose · Post by **cgreygoose** » 16 Jan 2014, 12:22

OK. I think I found the problem. When I turn on the headlights there is a very quick and slight click that happens inside the the fuse area behind the gear selector. I found a relay in there that was making the noise and once I reseated it nice and tight the dash lights came on properly.

Still no gas gauge movement which I will try to diagnose later today.