Printed Circuit Board - The 1947 - Present Chevrolet & GMC Truck Message Board Network

amloya · 08-24-2006, 03:21 PM

I just replaced the printed circuit board on my 70 Custom 10. Half the dash lights were not working, but all gauges worked fine. Now that I have replaced the circuit board, all of the dash lights work fine, but the brake light (on bottom left side of fuel gauge) works some times and others not. Also, the tachometer works OK if headlights are off but when I turn headlights on, the tach revs up to 4500 rpm and works backwards. When I accelerate, it goes down to 3000 rpm as if it was wired up backwards. This only happens when the headlights are turned on. Any ideas what might be the problem?

08-24-2006, 03:21 PM	#1
amloya Registered User Join Date: Aug 2006 Location: Texas Posts: 29	Printed Circuit Board I just replaced the printed circuit board on my 70 Custom 10. Half the dash lights were not working, but all gauges worked fine. Now that I have replaced the circuit board, all of the dash lights work fine, but the brake light (on bottom left side of fuel gauge) works some times and others not. Also, the tachometer works OK if headlights are off but when I turn headlights on, the tach revs up to 4500 rpm and works backwards. When I accelerate, it goes down to 3000 rpm as if it was wired up backwards. This only happens when the headlights are turned on. Any ideas what might be the problem?



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