Dash Printed Circuit Replacement Issue

[BSC73]

Hello everyone, a little background information I currently own a 1973 Mustang Mach 1 351 Cleveland 4v Q code.

I recently replaced the printed circuit dash gauge on my mustang with a new replacement off of NPD which I will link to at the end. I also took the opportunity to replace my gauge lights since I pulled the dash out and used a led kit from NPD, which I will also link. When I went to check the lights by reconnecting the dash, none worked except for the turn signal lights. Does anyone know what might be the issue? Any suggestions are appreciated greatly, thanks.


Links:
https://www.npdlink.com/product/pri...%2Bdash&top_parent=200001&year=1973&year=1973https://www.npdlink.com/product/led...cluster&top_parent=200001&year=1973&year=1973

 

[c9zx]

Led bulbs are polarity sensitive, try reversing the way you put them in. The main connector may be corroded or inserted improperly. Chuck

 

[70sElvis]

X2 on the above. I had to test each one because mine were not marked but that fixed them.

 

[mrgmhale]

X3 on reversing the LED bulbs, as they are polarity sensitive.

 

[DaveMT]

You can hook up each one of the LED Bulbs to a 9-Volt battery to test them. The attached diagram shows which side of the bulb needs to be connected to positive 12-Volts.

 

[DSwan]

You can hook up each one of the LED Bulbs to a 9-Volt battery to test them. The attached diagram shows which side of the bulb needs to be connected to positive 12-Volts.

I tested my cluster lights on the bench using a 9-volt after installing led bulbs as you outline. It worked great and kept me from having to r&r the cluster several times.

 

[mrgmhale]

I tested my cluster lights on the bench using a 9-volt after installing led bulbs as you outline. It worked great and kept me from having to r&r the cluster several times.

Thank you for sharing the results of the suggestion from DaveMT. It looked like a solid suggestion. Good to know you concur.

 

[Steve1973M1]

Hi
VX7805-1000 ( cui from digikey 102-4253-ND)
inserted inside old metal regulator shell is an upgrade to all of your instruments. You have to ground terminal 2 to case ,Terminal one is input and 3 is output. You will get 5v fixed short circuit proof dead on. The fuel gauge should be recalibrated with an 11 ohm resistor for full tank and 75 for empty. You realy only need to do full if it worked before. Below is older regulator on back of instument panel and a Gauge from rear. The one that goes to fuel gauge is the output. The Gauge is showing high adjust and the one on right is zero.