1973 Mach 1: No instrument lights

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dinkygreg

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Dec 30, 2010
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Location
Texas
My Car
73 Mustang
Yesterday I installed a new stereo in my 1973 Mach 1 and when I went to drive the car last night I had no instrument lights. I checked the fuses and they were fine. I am pretty sure about the stereo wiring connections, because I done this task many times. I really have no idea, what else I need to check. If anyone has any ideas/fix, I'd like to hear them before I take the dash back apart.

Thanks in advance.

 
Check and see if the headlight switch knob is not turned to dim the instrument lights.I dissassembled my dash two or three times before I figured it out . I felt like a dumb a#$#. Try It an see.

 
If twisting the switch does not work, try pulling the fuse out and either reseat it or replace it.

 
Hello,

You also could measure the voltage on the "Lt Blue-Red" wire direct on the light switch. It should be + 12VDC if you switch on the headlights and turn the position of the dimmer to max (rotate to left).

If there is 12VDC there are 2 possibilities for a failure:

a.) Problem with the positive wiring. Therefore check the voltage also behind the 4A fuse (2-nd in the line with the 4 in parallel fusing) If fusing is OK check the voltage direct at one the instrument light

b.) Problem with the common grounding. All instrument lights have one common grounding connection. This could be checked if you measure the voltage between the ground wire direct on the instrument lamp between vehicle ground. If the voltage is 12V instead of 0V you have a problem with this common grounding connection.

If there are no 12VDC, you have to check the incoming power supply to the light switch. Or check the switch.

Maybe this will help you.

 
Last edited by a moderator:
Hey guys I'v got the same problem. Connector I cut off to power up the stereo has 3 wires (white pwr,white with stripe - remote I guess,n blue for ground) & if I connect them all together n turn the key my dash lights work whether I pull light button on or not. Did not have problem b4 installing the stereo. Could it be I'm using a wrong wire to power up radio?

Please provide help. Thanks

72, 351c, conv.

 
Hey guys I'v got the same problem. Connector I cut off to power up the stereo has 3 wires (white pwr,white with stripe - remote I guess,n blue for ground) & if I connect them all together n turn the key my dash lights work whether I pull light button on or not. Did not have problem b4 installing the stereo. Could it be I'm using a wrong wire to power up radio?

Please provide help. Thanks

72, 351c, conv.
Hey, sharpstang. Try starting a new thread for your problem and you might get some more people taking a look at it, since this one is kind of stale.

Good luck -

Doc

 
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