Question about A/C Panel Lights - Not coming on as normal

[jawn101]

So I'm baffled by this. Up until today, my A/C panel lights worked as designed - always on with the key, regardless of the status of the LMS. I jumpered out the rheostat long ago because I have all LED panel lighting, which is why I like the original design rather than the "on with LMS only" style.

Today, the A/C panel lights don't come on at all. If I remove the relay and jump it out per the mod at http://www.dmcnews.com/Techsection/acpanellites.htm (basically connecting the A/C panel lights directly to ground) they work perfectly when I turn on the headlights.

I tried swapping in a different relay and it didn't help. The schematic is very hard to understand in this situation because there are tons of light green and red/orange wires that just vanish into huge bundles of light-related goodness.

I pulled out the red resistor and verified that it's not burned out, and that it reads as a resistor - not quite sure what it does, frankly. I do know that I tapped into one of the pins on it for key-on signal for Dave M's solid state dome light timer.

Does anyone have any idea what could be going on here?

[DMC5180]

Do your Windows move up/down. If not, check fuse 11

That's the supply feed for A/C panel too.

Remove the A/C panel relay and probe terminals 87 and 87a. You should see voltage on both. 87a (center) LG/W should be battery voltage. 87 will be reduced voltage from the resistor.

The resistor was used to drop the light level for night time illumination.

When the headlights are off in Daylight. The panel is at full brightness for daylight conditions.


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[jawn101]

Yes, windows work fine. If the fuse was shot I imagine the jumper in the relay socket wouldn't work, right?

[jawn101]

And when you say probe 87 and 87a, do you recommend the probe go to the ground pin in the relay or straight to the battery, or...?

[DMC5180]

Yes, windows work fine. If the fuse was shot I imagine the jumper in the relay socket wouldn't work, right?

No, when you jumper, you are using the 12v power that would normally just energize the relay coil. That feed comes from the headlight switch (R/O) wires. It's a separate circuit.

It does confirm the wire Circuit from the Relay relay to the panel is GOOD.

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[DMC5180]

And when you say probe 87 and 87a, do you recommend the probe go to the ground pin in the relay or straight to the battery, or...?

If you are using a 12v test light, connect the alligator clamp to Ground. Probe the Relay socket for Power.

Also make sure the thermals all appear to be seated in the top of the socket.


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[jawn101]

If you are using a 12v test light, connect the alligator clamp to Ground. Probe the Relay socket for Power.

Also make sure the thermals all appear to be seated in the top of the socket.


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What do you mean by all thermals? The thermal trip breakers? What about seating them?

[DMC5180]

Socket terminals, make sure none have been pushed down.


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[jawn101]

Socket terminals, make sure none have been pushed down.


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Oh, I gotcha. That was the first thing I checked - I did find that my (PO installed...) starter relay TSB mod used a terminal with no retaining clip so it was being pushed out slightly, but I fixed that. The others all seem OK. Will do some more ground testing today.

[DMC5180]

Not sure why you are saying Ground Testing. All Wires ( except Black or trace / Black ) are Live or Switched +12 V. You are looking For Power not Ground.


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