Heater fan wiring identification?

[DEA AK]

Hi everyone,

New to me m1097a2 doesn't have the heater fan switch... does anyone know the wiring numbers so I can by a local switch to temporarily get it working while I wait for a real replacement?

Thank you!

 

[Mogman]

39D looks like the switch feed, 400 goes to the fan motor, it will be on one side of the resistor mounted to the firewall behind the inst. panel, basically supply 24V to one side of the resistor for high and to the other side for low

 

[Mogman]

On your other post has me wondering, which fan are you talking about, the heater fan does not need to be run to evaluate the cooling system.

 

[DEA AK]

On your other post has me wondering, which fan are you talking about, the heater fan does not need to be run to evaluate the cooling system.

I thought that I saw before that you needed to run the fan and have the heater turned up to allow the coolant to flow through the system so there were no air bubbles or whatnot.

I don't know, this is completely new to me so I appreciate the input / feedback / help that everyone is providing.

Thank you

 

[DEA AK]

39D looks like the switch feed, 400 goes to the fan motor, it will be on one side of the resistor mounted to the firewall behind the inst. panel, basically supply 24V to one side of the resistor for high and to the other side for low

Thank you very much, I appreciate it.

This wasn't a planned purchase and I am having the hmmwv delivered tomorrow and I have to get it up and running ASAP. Apparently the DOD had all fluids dumped because they were going to crush it. So in addition to the oil, tranny, etc I have to do the coolant and brakes which I've never done on a vehicle before.

Thanks for the help, I appreciate it.

 

[Mogman]

The heater core does not care if the fan is on or not, unless your truck came with factory AC the heater water flow is controlled by a cable on the dash, it leaks by enough anyway so that is a non issue.

Make sure to use spec fluids, DOT 5 SILICONE brake fluid ONLY, not 5.1 and yes it is very expensive.

Use green "old school" coolant, you just fill it to the line on the reservoir, could not be simpler.

There are many you-tube vids on bleeding the brakes.

Make sure all the brake bleeding screws are in place and can be opened before starting.

If your truck was truly headed to the scrap heap I would expect to find drain plugs missing and maybe even a hole or two in the trans pan and or fuel tank.
INSPECT EVERYTHING, hoses, clamps fittings, wire connections, extra time here will save you money in the long run, remove the check valves located in front of the fuel tank, do not forget you have geared hubs behind the wheels that need servicing.

Do NOT push as hard as you can on the brake pedal while bleeding or any other time while the engine is running, you can possibly blow the seals in the hydo-boost.

The maintenance, operator and parts TMs are an invaluable resource, take the time to read and understand them before starting on your truck.
Nobody likes homework but it will give you a MUCH better understanding of your truck, if you are not willing to spend time with the TMs then it would be far better to have a pro familiar with the HMMWV do your work as it is a very different animal.

Here is alink to the TM sticky, the first link will take you to a site that has all the TMs you will need to start.
https://www.steelsoldiers.com/threads/hmmwv-technical-manuals-if-you-need-it-its-here.189594/

 

[DEA AK]

The heater core does not care if the fan is on or not, unless your truck came with factory AC the heater water flow is controlled by a cable on the dash, it leaks by enough anyway so that is a non issue.

Make sure to use spec fluids, DOT 5 SILICONE brake fluid ONLY, not 5.1 and yes it is very expensive.

Use green "old school" coolant, you just fill it to the line on the reservoir, could not be simpler.

There are many you-tube vids on bleeding the brakes.

Make sure all the brake bleeding screws are in place and can be opened before starting.

If your truck was truly headed to the scrap heap I would expect to find drain plugs missing and maybe even a hole or two in the trans pan and or fuel tank.
INSPECT EVERYTHING, hoses, clamps fittings, wire connections, extra time here will save you money in the long run, remove the check valves located in front of the fuel tank, do not forget you have geared hubs behind the wheels that need servicing.

Do NOT push as hard as you can on the brake pedal while bleeding or any other time while the engine is running, you can possibly blow the seals in the hydo-boost.

The maintenance, operator and parts TMs are an invaluable resource, take the time to read and understand them before starting on your truck.
Nobody likes homework but it will give you a MUCH better understanding of your truck, if you are not willing to spend time with the TMs then it would be far better to have a pro familiar with the HMMWV do your work as it is a very different animal.

Here is alink to the TM sticky, the first link will take you to a site that has all the TMs you will need to start.
https://www.steelsoldiers.com/threads/hmmwv-technical-manuals-if-you-need-it-its-here.189594/

Thanks for the great info, 2 quick things;

A. I bought diff brake fluid yesterday but I will go get the dot 5 (looks like Napa has some).

B. I bought some coolant from walmart yesterday, it says it has ethylene glycol in it, not sure if it’s green.

 

[Mogman]

Thanks for the great info, 2 quick things;

A. I bought diff brake fluid yesterday but I will go get the dot 5 (looks like Napa has some).

B. I bought some coolant from walmart yesterday, it says it has ethylene glycol in it, not sure if it’s green.

That coolant should work, looks like the
NAPA Brake Fluid Mac's DOT 5 Brake Fluid
Is the stuff you need.

 

[Mogman]

Thanks for the great info, 2 quick things;

A. I bought diff brake fluid yesterday but I will go get the dot 5 (looks like Napa has some).

B. I bought some coolant from walmart yesterday, it says it has ethylene glycol in it, not sure if it’s green.

Believe me I am not trying to harp on this but this is an example of why you should familiarize yourself with the TMs first so you know what fluids etc. to use.
If you had filled your system with DOT 3 (or 4 or 5.1) you would have contaminated it, the only way to correctly clean up that mess is with a complete tear down of the brake system which is a ton of work.

 

[DEA AK]

That coolant should work, looks like the
NAPA Brake Fluid Mac's DOT 5 Brake Fluid
Is the stuff you need.

Thank you