Myfirst85

Can anybody tell me why my electronic speedo and odo goes out whenever my headlights go on? I have yet to try to explain that to a cop but would rather not. Any help/info would be INCREDIBLY appreciated.

Scorpner

iTrader: (4)

I do know that the display dims when the headlights come one. I think over time though the display becomes weaker as it's hard to see mine during twilight hours.

That being said, there is an adjuster wheel on the LH pod (on the side of it where it says "panel") that controls how bright the display is. Maybe that can be adjusted. All of the display lighting including the radio respond to it and it is brightest when the wheel is moved upwards.

Myfirst85

It's not a dim at all. During the daytime, my dash is bright. As soon as I turn the headlights on, it goes completely black. my turn signals still light up on the inside and so does all the other indicator lights (my check engine is on and off constantly) My battery is newish and every other electronic part on my car works just fine.

Scorpner

iTrader: (4)

The turn signals and check engine lights are on a completely different circuit and are irrelevant to your issue. You should be comparing the oil, alt, temp and radio lighting to the MPH and tach brightness as the dimmer switch is moved. Did you try adjusting the dimmer control?

John in RI

iTrader: (167)

If ( with headlights on ) you attempted to adjust the rheostat dimmer on the Blinker pod and got no response then either your Light Module is dead and needs to be replaced ( most likly problem ), or the rheostat dimmer switch is not making contact with the circuit board inside the pod. ( possible - not probable. )

Bellrose

Hey, I have the exact same problem with my Berlinetta. In replaced the light module but there was no change. Hopefully I don't have two faulty modules. Did you ever fine the problem? To me, it sounds like there's a grounding issue somewhere. Please let me know what happened with yours. My email is rbellrose@hotmail.com

John in RI

iTrader: (167)

Bellrose: If this is the problem you are having the "dimmer" circuit is the cause and my last post to this thread explains what to look for. It's VERY possible that you installed another faulty LM as this dimmer circuit failure is common.

Get a voltmeter and do some testing before throwing any more $$ at the problem. Either switched ground ( or switched power ) probably is the issue & it's most likely a problem INSIDE the Light Module !

P.S. when adjusting the dimmer rheostat on the Blinker pod try to push it towards the dash while rolling it up & down. This will sometimes allow better contact at the rheostat. ( I've seen match-books stuffed in front of that rheostat control many times over the years !! )

Bellrose

Thanks for the advice John in RI. After playing around last night I'm fairly certain that I've isolated the problem to the digital cluster unit. I see what you're saying about the dimmer switch in the left pod; however, all of the incandescent lights in the car which are dimable (the left and right pods, shifter and radio light) are all properly controlled by the dimmer. Because those lights are being properly controlled with the dimmer switch, the light module can be eliminated from the equation.

The only problem where dimming is occuring is in the cluster unit. This is what's going on. With the headlights off, the speedo, tach and all other lights function as expected. Another interesting twist is that my gauges (oil fuel temp and batt.) are all reading incorrectly. With the head lights on the speedo and tach go black and the gauges all peg. The oil, batt, and fuel all peg to the empty position and the temp pegs to the hottest position. If I turn my dimmer all the way down, I can see the speedo and tach in their faintest setting.

From the drawing I have, all of the gauges are tied into the solid state "computer" which also controls the digital display. So it makes sense that all of these problems are linked together. It is peculiar that the display works when the dimmer is at it's lowest setting but turns off when it is higher.

My guess is that the dim setting is the default for the computer chip and it has an external input to increase the the brightness of the display. Something to do with this external input is buggered and not giving the correct signal to the cpu when the dimmer switch is increased. This is causing the digital display to go black.

It would also be logical is it was a problem external to the computer chip as it appears to be affecting the performance of the gauges. My hope is that there is a blown resistor or capacitor which is controlling the power feed to the chip and the gauges. I hope this because it is easy to fix haha.

Then again I could be out to lunch on this one. Just my theory. I'll be looking into it more soon and I'll keep you posted. If anyone has their own theory, please let me know!

Bellrose

I regret to inform you all that I was rear ended two days ago and my car has been written off. I don't think they will let me buy it back, so it's going to the scrap yard. Looks like my digital cluster issues will remain a mystery. Truly a sad day for me