'98 V70 dash gauge lights out Topic is solved

[E Showell]

Dash gauge lights for fuel/temp, speedo and tach are out after flickering for months, but all warning lights seem to function fine. Loose wire?

Any thoughts?

[misha]

I would say that dimmer switch for instrument illumination is failed.

[cuhfs]

Ignition switch issue. Try jiggling the key a bit...after car is started. My 98 V70 has had similar issue since I bought it (many years ago). The "key position" is the key (... no pun intended).

[E Showell]

Rich, I don't think it is a key position issue. I had that with an old 850 and the symptoms aren't really the same. Misha-- I'll check the potentiometer (if I can figure out how to do that). Thanks.

[scot850]

Evan, be very careful trying to remove the potentiometer. As you know it sits to the right of the light switch, but it has 2 very fragile spring clips (diagonally opposite each other on the long side). The clips are not the fragile part but the plastic position on the sides that they fit into on the potentiometer are and become more so with age.

I think I paid about $75 for one a couple of years ago from Tasca:

http://www.tascaparts.com/volvo/s70/684 ... ame=switch

If you look at the link you can see in the head-on picture of the unit the spring clips to the sides.

Most successful way I have found to get them out is to remove the light switch (Carefully prize out the main square center section using a non-marring tool. Then prize out the switch to the right of it. You can then get fingers to either side of it and gently work it out. Even then there is no guarantee. I see many of them broken in PnP. You can jam them in if one spring breaks off and they don't tend to slide out in use.

It is worth checking the illumination bulb while you have it out. I buy the little LED bulb portion of the bulb and holder from Mouser electronics and swap them out. I think I paid about 50c/bulb. They also sell the shorter bulb holder and bulb as a unit:

Bulb part #/description is:

Part number is: 560-7219
MFG Part #: 7219
Made by JKL Lamps.


http://www.mouser.com/Search/Refine.asp ... d=560-7219

I have pulled many of these over the years and have only replaced the one and that was because the one in my car had both springs broken off. Unit still worked fine.

Neil.

[E Showell]

Yeah, I'm not thinking the potentiometer is the problem. I guess it could be the light switch itself, but the intermittent blinking up to now really suggested loose wire to me.

[E Showell]

Potentiometer doesn't seem to be the problem. Lights, when working, go dimmer and brighter with a spin of the potentiometer.

[scot850]

Well one possible cause down.

If I recall there was a recall for problems with the light switches on the P80. They are usually cheap at PnP (again I had a spell of pulling all of them I saw at PnP) so swapping may be an option as a further stage of elimination. My final suggestion as it appears to be only affecting the main dash lights is perhaps there is a problem with the main connector to the speedo cluster. That requires removal of the dash to access. Not too difficult. Hardest part is to undo the airbag on the passenger side (4-5 small nuts under the top lip of the glove box. If you look to so this make sure you disconnect the battery for 30 mins before trying to remove the airbag.

This would also be a good opportunity to swap out the bulbs on the speedo cluster while accessible.

Neil

[E Showell]

Thanks, Neil. I've pulled the dash to do the main gauge bulbs before (and I had the flickering before I did that too).

[scot850]

Look at the back of the speedo cluster. I recall folks having problems with the circuit board failing. Check all the contact pins and clean using electrical cleaner and let it dry before re-connecting it. Check all the pins for damage. I know there was a light relay somewhere in the system. Again maybe worth a check for connection/operation.

Neil.