Still Inside the Dash - '51 300 - Voltage Regulator

Posted by Dave Merrick On 2010/11/15 14:19:23

Well Here I am again with the ongoing saga of my instrument cluster repair.... He he a LOT of fun :)

I have a question about the voltage regulator for the temp/gas gauges. I have grounded it with alligator clip lead and am taking a no-load reading between the regulator output and ground with my old trusty Simpson analog meter. The voltage is bouncing between 6v and 0v almost like a turn signal flasher would. I don't know how these old regulators operate. Do they need a load to operate properly or is this one toast? Also, how many amps are pulled through them? Can I pop in a modern 7905 voltage regulator in it's place? They are rated for 1A.

My Temp gauge always seemed to run high (Before and after a full service of the cooling system) And my gas gauge will only operate between 1/4 and 3/4 full. Previous owner just installed a new gas sending unit from Max Merritt before I purchased the car. Could these be symptoms indicative of a bad regulator AND a bad ground going to the cluster?