OK folks here we go. The old ranchero MX has developed the dreaded crazy gauges syndrome known to all of us as bad voltage regulator on back of cluster. Well I decided to buy one of those electronic replacements from NPD and it works even worse! So for laughs went in and checked the input voltage and all I have here is 10.2 V with an out put of only 4.3 V. I know I need 5.0V out for the gauges to work properly. The battery with car off is 12.7 V and with the car running is 14.5 V. So whats up with the 10.2??? Any suggestions. I checked connections for corrosion and cleaned still 10.2. Do I need a full 12v? I would think so but please give your input. Thanks, Dan
Just went out again and did some voltage checks and ended up putting the old factory style regulator back in and works better but not right. That is why I wanted to try the solid state one. looks like I have to look at something else.
Every connection needs cleaned starting at the fuze-links at the starter solenoid going into the car. My money is on the pins in the bulkhead connector by the brake booster, Dan.
I am able to get 12 @ The connector on the back of the cluster. But when the regulator is plugged back in it drops off to 10v
I know there is a direct ground from cluster harness connector to dash firewall.Maybe worth checking Dan.
From my collection of old photos here I find two that show the IVR; one has a series 'radio choke' -- and the other doesn't. But ff your has one, try measuring the resistance of it; should show 8 - 9 ohms. If you measure input voltage directly at the IVR, and it isn't the same voltage as the battery alone, then look for a failed radio choke. It appears as a separate piece, not part of the IVR. (this appears on a 1973 Torino chart) It's worth mentioning that if you check it with the ignition switch 'on' then you are measuring the output of the thermal breaker, not the average output voltage.
