Recent content by jawalter

Voltage Gauge Testing Do you have a variable DC power supply that you can use for troubleshooting the gauge? If not, you could try hooking up three 9V batteries in series with the guage to see if it reads approximately 27V.

It looks like a 24V gauge based on the scale. From what you described, the gauge appears to read the dual in-series 12V battery voltage okay before starting. Once the truck is started and the alternators are turning, you appear to have more voltage than the gauge can handle. Disconnect the...

The "old" voltmeter sounds more encouraging than the "new" voltmeter. Not getting any needle movement with the "new" voltmeter sounds like the "new" meter movement might be damaged. Do you have a bench top variable DC power supply to check the gauge movements? If not you could try connecting...

Voltmeter Testing The safest way to check your voltmeter is to connect it to a dc power supply and slowly increase the voltage on the power supply until the gauge's needle is centered in the green zone. If it takes ~13V to center the needle in the green zone, and your vehicle has a 24V...

I would suggest removing you gauge from the instrument panel. Get a digital multimeter and read the voltage between the 2 wires that were connected to the back of the gauge. If you get 24VDC with the truck running, I would say that your charging system is okay and the needle reading on your...

Green Zone The needle on my gauge stays pretty much centered in the green zone after my M1009 is running.

I think you are on the right track. I would try replacing the vacuum modulator. I don't think they are too expensive. Let me know how it turns out. - Jeff

Here is a message that I posted about 2 weeks ago. It might help you with your transmission shifting problem. I’m posting this message to thank everyone on this thread for sharing their knowledge. Your advice and tips helped me fix my late shifting problem with my M1009. My M1009 was shifting...

I attached a wiring diagram to show you how to do it. This method preserves the original wiring just in case you want to put it back to the way it was originally. However, I think you will be happy with the manual control of your glow plugs. I'm using AC Delco 60G glow plugs that are self...

I found my problem this past weekend. My problem was the glow plug relay. Even though I would hear a click when I energized the coil with the my manual toggle switch, the glow plugs weren't getting voltage. The contacts inside of the old sealed relay are probably bad. Sometimes the relay...

The last time I checked my glow plugs was about 2 months ago. At that time, 7 of the 8 were good. I will check them again today. I'm supplying the AC Delco 60G glow plugs from the resistor bank. I had my resistor bank off a couple of weeks ago to fix the loose rivet nuts that are in the...

I had some trouble starting my M1009 yesterday and was wondering how long you should crank the engine. The outside air temperature was ~45F. I have a manual glow plug system installed using AC Delco 60G glow plugs. My glow plug relay is controlled by a momentary toggle switch. My glow plugs...

The ceramic resistor is only for the voltage gage. The 300 ohm resistor is one half of a voltage divider circuit. The other half of the voltage divider circuit is the internal resistance of the 12V gage itself (~190 ohms). When 24V is applied to the gage circuit, more than half of the 24 volts...

You might be able to fix your voltage gage. The gage is actually a 12V voltage gage. On the back of the gage there are 3 threaded studs. A rectagular ceramic resistor connects two of the threaded studs together. The 300 ohm ceramic resistor is part of a voltage divider circuit that reduces...

I’m posting this message to thank everyone on this thread for sharing their knowledge. Your advice and tips helped me fix my late shifting problem with my M1009. My M1009 was shifting from first to second between 25 and 30 MPH. It shifted from second to third between 50 and 55 MPH. Here is...