3 Attachment(s)
Willys Truck Gauge Clusters
Guys: I'm redoing a 1952 Willys stake bed truck, see attached, and I am having trouble with the temperature gauge. The truck starts and runs well, but after a few minutes the temp gauge pegs to hot. I have replaced the water pump, thermostat, 6 volt sending unit (it is still a 6 volt system), and the radiator. It still shows hot, but I have had two inferred temperature guns on it and it never gets above 190 degrees, even after running for an extended time at the stand still. My parts book shows what is called a voltage regulator that mounts on the back of the instrument cluster and the output side goes to both the gas gauge and the temperature gauge. I put in 5 gallon of gas after cleaning the lines and replacing the fuel tank, and the gas gauge showed about 1/2 full. I think this is also high for a 15 gallon tank. I tested the voltage regulator on the gauge cluster and I get the same reading in as out, all above 8 volts. I'm thinking this device is not working properly, any thoughts? Thanks.
Attachment 10374 Attachment 10375 Attachment 10376
1 Attachment(s)
Instrument Voltage Regulators
[I]"The regulator I have to be used as a replacement regulator to the one not working reads 42.7 ohms ign to case, and 7 ohms ign to output."[/I
This is probably more than you want to know:
The attached picture is a diagram of what is probably inside your voltage reducer. (The IGN to output probably should be drawn as a normally closed set of contacts, but ...). There is a bi-metal strip wound with a heater wire. There are two sets of contacts on the bi-metal strip. One set of contacts controls power to the heater. When the strip is cold, the heater turns on, warms up the strip and as the strip bends, it opens the contacts. Once the strip bends and the switch contacts open, the heater cools off, the strip returns to its original position and the process repeats. This heater circuit is the 40-ohm circuit you see from IGN to CASE.
The bi-metal strip has a second set of switch contacts that connect the IGN terminal to the other contact on the regulator. These contacts are the contacts that open and close to produce the “average” voltage to the instrument cluster.
The procedure you found to test the regulator calls out zero-ohms from IGN to the regulated output – a closed set of switch contacts. If you are reading 7-ohms across those contacts, they are damaged. That resistance will add 7-ohms to the resistance of the gauges that are sensing temperature, fuel level and oil pressure. The problem isn’t so much that the readings will be off a bit – but the points will eventually overheat and fail. They will probably weld themselves together.
If you can open up the bad unit – open it up and look at how the contact points are arranged. I suspect that the bad unit has welded points. If you can see how to get to the points, open up the good unit and give the points a good cleaning.
Or – just try the old regulator and see how it goes …..