Intermittent power to 3-prong bullet dash terminal (clock, tach..)

[DetSon]

Hello All,

So I'm trying to hook up the lights to three aftermarket gauges and tach. I thought a great place to grab power would be the three female bullet terminal that powers I believe the clock/clock light, tach light, and something else? from the original harness. It works off the light switch, existing, no problem right?
It seems to function as normal, no power unless I flip the switch to parking or full lights at which point I get 10.5 v I believe. The tricky park is as soon as I touch a "load" or the bullet terminal for my gauge lights, I lose all power to that connector. I tried cutting it off thinking maybe something was wrong internally with the connector but no luck. I hold the gauge to it, I have volts, then touch something to the wire and it immediately goes to zero.
I am about 3/4 of the way of going through all my wiring, possibly more, so most/all of the demons are gone, good grounds, etc, not to say there's not still a problem. All the other interior lights are working. My main factory gauge panel is not hooked up currently, I'm not sure if that's influencing it. The high beam switch also is not hooked up now that I think about it. I just finished putting mat on the floor pans but that's an easy fix.

Anybody have any idea's what causes the loss of power?
Thanks

 

[patrick66]

You might consider running the wiring for the gauge lights to the fuse box, to the ignition-on side. You'll have lights to the gauges whenever the ignition is "on", and they will not be dimmable; but you'll have the lights everywhere you are supposed to. It sounds like that connector was never designed to have other power draws hooked up to it.

 

[DetSon]

I just wish I could trigger them with the light switch. I guess it wouldn't be awful to have them running all the time just to bring more attention to them.

 

[JedIEG]

If it is the orange three pin connector (atleast for E's and 71-74 B's), it should work for your gauge lights. Those wires should all run from the adjustable power out on your headlamp switch to the gauge lights, ash try light, and console shift light. Make sure you are not grabbing it from the dome light ground connector (yellow) Battery feed connector (red) or Accessory connector (yellow) because they are all the same three pin connector. I would suggest checking a stock gauge bulb socket's voltage and see if you have to same problem. If not, check the switch. The last harness I did had some really weird problems before everything was hooked up that I can explain. I didn't have some of the lights hooked up and when I put the turn signals on, the brake lights would flash too. Once everything was together it fixed itself.

 

[DetSon]

Yes it is that orange 3-prong. I believe from doing a little research it might be the way the light on the gauge itself that's causing the problems? It is a single wire light bulb with a ground to the casing. I still don't understand it but some people stated that that would not allow you to dim the lights. For now I just tied it to the light switch so they come on with the parking/headlights, which is fine for me.