check panel 12v when pressed intermittent for voltmeter

[barbierij]

Does anybody know which pin has 12v intermittently when the 'check' button is pressed and illuminates the lamps for a short time? I have a check panel with a volt meter that sits on a shelf. I don't want to drive around with a bright volt meter all the time, but it would be nice to have when I press the button.

update:
Figured it out while thinking about dumb things. The backlight turns on when you press the 'check' button and remains on for a few seconds. This light gets 12v+DC constantly and a transistor gives it 12v-DC.



these are the sources from the back:



I realized the wires wouldn't fit when closed, so I went from the component side of the board:











Hope this helps everyone out! iron tip I used was set at 665degrees

I'm sure some scumbag is going to charge much more for their checkpanels now that include this feature

[jgilber0]

Cool idea!

[BeirBrennerE30]

There is someone selling volt meters built into hazard buttons that turn on when the button is pressed and turn off when pressed again. I dont remember who though. Not exactly what you are looking for but maybe would work.

The check panel is self contained and there really isnt a signal sent out when the switch is pressed. There are relays at the lights, in the power dist. box, etc. that the check panel checks. You may be able to use the signal to the gauge cluster. It would be the blinking signal that flashed check until the button is pressed. I think the gauge cluster just has the bulb and the check panel controls it but I am not sure, you may want to check to see what that wire does exactly. Gauge cluster plug C1, pin 4 to check panel pin 2, wt/bk wire (at least on the early cars as far as I know). It would only display your units when the car first starts until you hit check but you could have a micro display volts on turn on and then sense the blinking and if the blinking stops the volt gauge turns off. It would then stay off until you restart the car or until something happens that would turn a light on in the check panel. You could maybe highjack the washer fluid level sensor (or some other warning light) by adding a switch to turn the volt meter back on but that warning light would also turn on with it.

[barbierij]

bump after update