Whats the best way to test a guage?
I have a multimeter and can rig 24VDC.
I dont want to have to put it in the control panel and run the engine if I can help it.
I have several in my spares box, courtesy of the previous owner. I want to put a 60 - 260 in instead of an odd looking one that has a much larger range. I also have a pressure guage 0 - 120 and am wondering if the testing process would be the same?
If you have a 24v power supply you should just be able to hook it up with a couple test leads. A variable supply would work better as you could test various voltages, eg 12, 18, 24v
If the pressure gauge has a copper tube, make up an adaptor to a regulator on a compressed air line to see if it reads
The original military gauges are a bit more complex. They not only use a grounded circuit through their sender to measure the change in resistance they also require a ground path for the instrument's motor power.
The proper way to test these instruments and their senders is in accordance with the Army TB 9-2300-228-20 Tactical Transport and Combat Vehicles: Troubleshooting for Instrument Cluster Gages, Switches, Circuit Breakers, Sending Units and Related Wiring dated 8 July 1960.
Remember when you have a gauge issue always check the sender's ground, the connections at the sender and Gauge and the gauge's housing ground through the dash. On my M series trucks I add a separate ground cable between the instrument cluster assembly and the firewall. If you have repainted the gauges and the cluster panel and have not left bare metal contact area for each gauge housing to the cluster panel and for the cluster panel to the dash then it would be wise to do so now or add a separate ground wire for each gauge to the firewall.
Thanks for your help guys, I am now looking at the manual Wes. Thanks.
I need to do the extra earth wire for the fuel guage anyway as it is a bit erratic. So will put in one of the temp guages and see if it works.
Andy
The fuel tank can be the worse for finding a good ground. Too much new paint always. Generally a separate 16 gauge wire from the tub to one of the screws on the sender is all that is needed.
