Bulb indicator light - why?

Andrew Vanis · Post by **Andrew Vanis** » 13 Jul 2024, 20:58

Bringing the 97 v70 back on line.

(Pics)

When first started the car after singing for years, it showed the bulb light in the instrument cluster when ever either lights were on or the brakes were applied.

Now the bulb indicator comes on only when brakes are applied (doesn't matter if lights are on or off)

Since it fixed the lights on issue, I'd be tempted to let it self-fix the brake issue too but I got to deliver this to my kid in a few days so would like to fix it.

Here is what it looks like from the back. Top pic is with lights and brake on, bottom is with just lights.

Post by **scot850** » 13 Jul 2024, 23:06

Maybe it the the angle, or the lighting, but the right upper light in the last photo looks dim. The test system measures for the current passing and if it is not sufficient (dim) it may be throwing a code.

Again maybe the lighting but the lower left light looks like it has a double light reflection and the one on the right a single. Is the correct bulb in there?

It may be worth going through all the bulbs and checking the correct ones are fitted and the bulb seats are not corroded.

Neil.

Andrew Vanis · Post by **Andrew Vanis** » 14 Jul 2024, 07:21

Another set of eyes is always helpful. I'll check the relatively dimmer bulbs. May be insightful to use the DC amp meter and see what is drawn.

Thanks for the reply.

Post by **scot850** » 14 Jul 2024, 09:03

Hopefully it is of help.

Good Luck!

Neil

Post by **Clemens** » 14 Jul 2024, 13:05

There are 2 versuons of that 3rd brake light module. One is for the bulb version, one for LED. If they are incirrectly used, it can cause the light to go on.

Post by **volvolugnut** » 14 Jul 2024, 13:17

I have had troubles with rear lights on my 2001 V70. The bulbs need to be the same brand with similar resistance. The bulb holders can get bent contacts and the light housing itself can get broken plastic tabs that hold the bulb holders.
All can lead to intermittent or poor electrical contacts and bulb failure light on.
volvolugnut

Andrew Vanis · Post by **Andrew Vanis** » 15 Jul 2024, 08:43

An update - the indicator light has reverted being on with the headlights, not just the brakes.

I appreciate all the comments above and the idea of different resistance of different lumens / intensity and possible corrosion or connection integrity as something to follow up on. Thank you for making me aware of that possibility that the bulbs could work and still trigger the indicator right.

Post by **scot850** » 15 Jul 2024, 13:38

I have not had this issue on a P80 with different brands of bulbs, but I know it is more of an issue on newer Volvos.

Maybe there is a bad ground if the indicator comes on when not being called for.

Neil.

Post by **Clemens** » 15 Jul 2024, 15:02

And remember to always check the battery voltage and alternator performance if any electricsl hiccups or warning lights appear.
And the possibility of a worn electrical switch in the ignition key assembly.

454cid · Post by **454cid** » 17 Jul 2024, 11:59

My bulb out indicator comes on periodically with my brake pedal depressed. The 3rd brake light somehow loses contact and hitting it fixes it for awhile. This is the shelf mounted version in my 96 850, not the later roof mounted version like my S70 had.