Installed LED backlighting, now analog gauges have issues

[spg356]

Greetings,

 

The title says it all. I installed LED back lighting in my 2001 996C4 and now the analog gauges are "wonky". Speedo goes up to 150mph and then back down while driving normally, amp gauge reads wrong, fuel gauge pegs past full, tach does not register at all etc, etc.

 

Has anyone experienced this before?

[Ahsai]

Are you sure all the connectors at the back of the cluster are fully plugged in? Do you have a Durametric? It can test the cluster.

[spg356]

Hi Ahsai,

 

Thanks so much for the quick response. To answer your questions-- yes and yes! It is really odd, all is connected properly and tested, but still issues with the analog gauges.

 

Any other suggestions are very much appreciated.

[Ahsai]

I take that those gauges swing to their full range when tested by the Durametric?

 

The next thing to try is remove fuse B1 and reinstall it. If that doesn't work, I suggest you remove all the connectors at the back of the gauge and reconnect them.

[spg356]

 I should clarify, while the gauges were “properly tested“ they behaved in their unruly fashion when tested. Sorry for any confusion. Also they were not tested with the Durametric, I have access to Autologic. 

[Ahsai]

Got you. If the above doesn't work, you may need to reopen the cluster and retrace all your steps. Maybe something inside has been disturbed.

[DBJoe996]

Go back to the last thing you did...swap out LED bulbs for standard bulbs.  Some circuits do not like the LED bulbs and this could be one of them.  Put your old bulbs back in and see what happens (because it wasn't acting wonky before you made the swap).

[judgejon]

Agree.  Same principles apply when changing out household bulbs to led's.  sometimes sockets, rheostats and other switches also need to be changed.

note that the issue may be with the instrument panel lighting rheostat.  Try turning brightness up and down all the way and see what happens.

good luck.

[wyovino]

I would suspect that the dimmer can't handle the low wattage of the LED bulbs. I know this may be apples and oranges, but I just went through some weird issues when I replaced incandescent bulbs with LEDs in my home. Replacing one of the LEDs bulb with an incandescent bulb fixed the issue in my case. It's a well discussed topic in lighting forums.