Electrical problems – instrument panel lights inverted

[MJ]

OK, I've got quite few electrical problems with an '89 1.7 340 and I was wondering if they sound familiar to anyone who may be able to identify the problem. There are several problems which may or may not be related.

A month or so ago problems stared with the instrument lights which were inverted. They were on when meant to be off and off when meant to be on. For example the blue main beam light was on when on dipped headlights but not full beam, and the indicator arrows were on constantly. This can sometimes be fixed with a sharp tap to the plastic screen.

A little bit more recently the illumination of speedo and rev dials stopped so you can't see the speed at night. The rev needle also drops considerable when side or headlights switched on. It still rises and falls, but stays bellow 1000 rpm or so.

These problems sometimes disappear, but come back. The problem usually exists in damp weather.

I noticed a while ago that the rear window heater didn't seem to be working, or at least not at full power.

Not long ago a strange noise came from the doors while the car was moving and since then the central locking doesn't work.

A friend said it sounded like an earthing problem as the battery seems a bit week if the car isn't started for several days.

Last week I took the car to the local Volvo dealer who said they fixed the problems, but low and behold they hadn't fixed the central locking so 5 minutes later I went back. Apparently all the motors in all doors have blown for some reason. They said there was corrosion on a fuse box which they fixed with spray stuff which was causing the instrument light issues, but they are still faulty.

Could the problems be linked, or independent? Any solutions?

I'm guessing a shorting wire behind the dash is causing the light problem as a tap fixes this. Probably in connection with the light switch.


Thanks for any help you can give.

[5lab]

behind the dash are 2 multiplugs - make sure they are plugged in - this can be checked by reaching from behind and under the dash.

[Chris_C]

Definately sounds like an earthing problem with your dash lights, if you remove the steering column shroud, try feeling behind the dash for two connectors, both are about 2 1/2" to 3" long, and give them a wiggle. Might be best to take your dash panel out (easier with the steering wheel off, but possible without) and have a look there, see if any moisture has got in there and has caused any oxidization around the terminals. This would also explain the rev counter not working properly and the fixing when you tap the dash

As for the central locking, was the noise a mechanical one? Like some connecting rodding moving inside the door? and can you hear the motors operating now? (I know Volvo said they have blown.....). This will need some thinking about if they have blown, as the 12V system shouldn't spike enough for the coils to burn out.

The rear screen is a common problem, do you have electric mirrors? if so check the connector that goes onto the switch, and the connector about 6"s further down the wire. If you don't have electric mirrors, then you won't have the second connector (I think.... doesn't hurt too check though)

Otherwise could be a connection come loose on the glass itself, have a look at both left and right side of the rear screen next time you go to the car.

Keep us updated, and I'll continue to think about the central locking

[MJ]

Thanks for the suggestions

Unfortunatly the torch battery died and there's a covering on the underside of the dash. I pressume the popper things need to be pulled out for the cover to be removed, right? I've never really looked down there before

If the weather's more permitting tomorrow I'll have a look again and see if I can set the cover off.

Yeah the doors did give a mechanical knock, but the sound hasn't repeated since. Apparently the controller bit in the drivers door has broken and sending bad signals. I presume the doors have motors that rotate a few degrees and are then stopped from rotating, right? In which case if current continued to flow after the motors had been stopped, isn't this bad for them?

I may have found the problem for the rear glass , the connection on the drives side of the glass seemed loose. I havn't checked the other side or the connector yet though, and you can't check if it's working very easily. (No electric mirrors by the way)

[MJ]

Well I took the cover thing under the dash off and there's a heck of a lot of wires under there, one wasn't connected to anything, presumably for an extra switch for some extra feature.

All connectors seemed to be plugged in alright and the wires seemed to be in good condition from what I could see. I tried to look at the connections to the switches with my head on the pedals and all seemed alright. The lights were still wrong after that but a tap fixed it leading me to believe the problem is actually on the instrument panel, so looks like it'll have to come out sometime, but I'm not to comfortable with doing that...

I looked at the rear glass and pushed the connector back on, so I think that that could have been the problem, I'll test it next time I go out.

Thanks for the help, but if anyone else has had a similar prob with the dash, I'd be interested.

[Lonewolf]

Not an orange wire by chance?

I havent had the problems you seem to have, but my old instrument panel would occasionally do the opposite of what yours did, you saying yours would show under 1000rpm through the whole rev range, mine would be idling and the dial showing over 6000rpm, sometimes it did it when the engine wasnt even on, just the accessories were. and the speedo would fluctuate by +-40kph and the fuel meter went backwards. I had the luxury of finding a spare instrument panel in better condition, so i swapped it in currently the only problem is the speedo fluctuations (+-15kph) which occur intermittantly, but that is also because i touched the speedo cable connection and took some of the graphite lubricant off and havent replaced it yet

As for taking the instrument panel out, its not all that hard, probably the easiest way to remove it

As its ur first time removing the instrument panel
1- Disconnect your battery
2- Take steering wheel off
3- Remove the 4 plugs that hold the plastic cover over the steering column
4- Reach behind the dash to remove the 2 flat white plugs that are clipped to the panel as well as the speedo cable
5- unscrew the 2 screws along the top of the panel and take the tapered plate off
6- tilt the panel forwards and carefully remove
7- Installation is the reverse of removal

The reason i made step 1 to disconnect the battery is that it is your first time behind there and i dont want you shorting any exposed live wires that will be touching your hand causing you to strip skin off or worse. After the panel is out and you have checked all the wires for exposed connections you should be able to safetly reconnect the battery and test away till your hearts content.

Also make sure the pins on the flat white plug actually connect, my spare instrument panel had no lights working on it, the corresponding pin was not making proper contact so after all the pins on the plug were raised slightly the panel came to life and all the instruments worked fine. Also when its all working either put some graphite powder on the speedo cable before u hook it back up or dont rub any off when interacting with it. hope that helps

[MJ]

I think the connector not plugged in had two blue wires connected to it.

Taking the dash out dosn't seem too hard. Is it possible to do it without removing the wheel? I'm not to confident about taking the car apart All of the other dials work fine, except when the lights failed to light.

Thanks for the advice, perhaps I'll get a friend around to help me do it sometime, I'm a bit unsure about all of this. As long as no shorts start a fire the problem isn't too bad if it stays, but I've got a fire extinguisher now

[lentinj]

Yep, it's possible to do it with the wheel still on---at least I can on my 340. You just have to replace step 6 with lots of swearing and cursing as you gently wiggle the dashboard through 90degrees so you can pull it out through the steering wheel. It's probably alot easier to just remove it, but at the time I thought it seemed a bit drastic!