Help Testing Dash Component backlighting prior to Re-assembly

[shanemasters1]

I am in the final stages of my lighting install on my 91 q45. I have the dash, gauge cluster, and all other components taken out. I would like to make sure that all of my new lighting works properly before re-assembling the dash. Tonight I connected the hvac controls, turned the car on, turned on the headlights, and turned on the hvac system. with the lights off the screen appeared normal. When I turned the lights on the display disappeared and no backlighting turned on. At the same time I had the clock connected. I have tested the clock backlighting with a 12 volt battery so I know it works on its own. When connected to the wiring harness at the same time as the hvac controls neither of them functioned properly. Could someone who has already gone through the lighting install provide some steps for the install and troubleshooting.

all help is appreciated.

shane

[1QIKQ45]

Hey buddy, Good idea, i think im gonna do the same thing.

Bump?

any body got any info?

[Q451990]

Is your dimmer switch plugged in? Without that, the illumination circuit is not getting voltage.

You could always rig a way to bench test everything with a 12V power supply, but you really need an extra set of connectors from a donor car to do it safely. Trying to get aligator clips on to those small pins is difficult.

Heath

[1QIKQ45]

You could always rig a way to bench test everything with a 12V power supply, but you really need an extra set of connectors from a donor car to do it safely.

I got those if you need them

[shanemasters1]

hello heath,

I did bench test everything I could with a 12volt battery on my bench. I am still working at understanding exactly the pin-outs on the fsm. I installed all my new leds in the gauge cluster, tested them on my bench. Now that I have installed them in my dash I am not getting any blinkers or gauge backlighting. I have the dimmer switch installed as well as the hvac controls, and clock. I dont see anything in the fsm on the blinkers or the backlighting.

I was reading your post on the "hvac trick repair" with the freeze spray, so I thought you might have some logical instructions on my current issue.

thanks in advance

shane

[Q451990]

Is your hazard switch plugged in? Also, you might try reversing the direction of the LEDs. They are polarity sensitive, and you may have had your test battery reversed... the FSM isn't really clear on which one is (-) and which one is (+) since it doesn't matter with conventional bulbs. If you trace the wiring diagram back all the way, you can find one that goes to ground...

Heath
Modified by Q451990 at 11:21 PM 11/23/2009

[Ozzie]

If you have changed out all the bulbs for LED's then I am going to have a guess at what the problem is.....

LED lights do not like to dim, as my main interior light used to dim ever so slightly.... then shut off (after changing to LED) . With conventional bulbs, it dims slowly over about 3-4 seconds....

The dimmer switch may be restricting the voltage slightly.... so when you have one or two things hooked up... the lights will work.Once you fully load the circuit up with everything (hvac, dash, clock, etc) there may not be enough voltage to run everything.

Conventional bulbs will still work, but they will appear a bit dimmer.LEDs will simply not light up at all.

You need to use lower value resistors in the LEDs. This should fix your problem, unless they are sealed bulbs.... which may make it more difficult to change out the resistors.

[1QIKQ45]

hope you get it fixed shane, and let me know when you get the armrestthanks