whacky gauge

[jinos]

Hi guys. Got some really weird things happening with with speedo. I just changed all the bulbs and now it won't light up. I tried puttin the old ones and still don't work. To make it worse every time I turn on the lights the gauge doesn't work. It goes right down to zero when I turn it on. When I turn it off the gauge works. What did I do wrong?

[Mr9146]

Originally Posted by jinos

Hi guys. Got some really weird things happening with with speedo. I just changed all the bulbs and now it won't light up. I tried puttin the old ones and still don't work. To make it worse every time I turn on the lights the gauge doesn't work. It goes right down to zero when I turn it on. When I turn it off the gauge works. What did I do wrong?

Sounds like you've managed to booger up a ground wire somewhere.

[ossiblue]

I'm not familiar with electronic speedos but here are some questions: First, did you change the bulbs in all the gauges or just the speedo?
Do the lights on your other gauges light?
Do you get voltage at the bulb terminal when the light switch is turned on?(test with a multimeter or trouble light.)
Did you change bulbs other than the instrument lights--such as a warning light bulb?
Are all the wires to all the illumination bulbs for all the gauges the same color?
I'd suspect a misconnection somewhere if your lighting circuit is working correctly. Keep us informed and good luck
And +1 on the ground wire!

[tcar]

Sounds like ground.

Ground wires are Brown (earth). It's been a while, but I vaguely think there are 2 of them on the speedo.

Other gauges work?

[jinos]

All other gauges work fine. I replaced all gauges just for illumination (8 bulbs). I saw one brown wire that was not connected to the speedo. I attached the brown wire and that's when all the problems started.