Electric Radiator Fan Not Working

[dannyloski]

So I was able to use successfully test continuity from terminal 85 (brown/light blue wire) at the relay all the way to Pin 2 on the green plug going into the TIPM (plug is labeled as “C”). So, I guess the wire is not broken anywhere along the way, which is a good thing.

Unfortunately, I think this tells me the issue is probably inside the TIPM itself. I pulled the TIPM and opened it up. There are no obvious signs of damage, so I’m a bit unsure how to go from here or how I can fix it. I’m not too familiar on how to do the PCB trace, any pointers? How do I trace terminal 85’s ground path?

PS: My truck is a 2012 Ram 1500 5.7L HEMI.

 

[RamDiver]

So I was able to use successfully test continuity from terminal 85 (brown/light blue wire) at the relay all the way to Pin 2 on the green plug going into the TIPM (plug is labeled as “C”). So, I guess the wire is not broken anywhere along the way, which is a good thing.

Unfortunately, I think this tells me the issue is probably inside the TIPM itself. I pulled the TIPM and opened it up. There are no obvious signs of damage, so I’m a bit unsure how to go from here or how I can fix it. I’m not too familiar on how to do the PCB trace, any pointers? How do I trace terminal 85’s ground path?

PS: My truck is a 2012 Ram 1500 5.7L HEMI.

That's excellent work.

I have worked with PCBs for many years, originally as an electronic assembler and then as a technician but I have zero experience with opening the TIPM. There are many members here that do have that experience.

I would advise you to use extreme caution while in there and do your best to limit any movement of the boards, wires, or sub-assemblies. It's like a huge interface with many circuit paths and the possibility of creating more grief.

I would do my best to examine the connector/wire interface because it is a large point of failure. Are you able to remove this connector and inspect the continuity through it? Is the wire soldered onto the connector, crimped, or insulation displacement?

I don't know if that PCB is a single-sided, double-sided, or multi-layer board. Single-sided is pretty easy to visually follow the traces, double-sided can be tricky but doable, multi-layer can be a big challenge.

If you do eventually find a damaged trace, post a picture and I'll let you know if I think it can be repaired and then talk you through the process.

Hopefully, someone who is experienced with TIPM troubleshooting and repairs will jump in and continue this adventure with you. I can only generalize now because I've never explored a TIPM myself.

I apologize, but I have to excuse myself now. It snowed all night and I need to start clearing snow. It usually takes me 4-6 hours after a bug dump. Good luck and I'll check in when I am able.

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[dannyloski]

All good, appreciate the help you’ve provided thus far. I did test the wires at the TIPM’s green “C” plug. They all have continuity, are securely crimped, and not damaged.

I reassembled the TIPM for now. Looks like I’ll be looking at different TIPM repair services and go with one of them.

Wish I could figure out what sends the ground signal to this wire, which then energizes the relay. Maybe with that info, it would help me be able to diagnose further.

 

[RamDiver]

All good, appreciate the help you’ve provided thus far. I did test the wires at the TIPM’s green “C” plug. They all have continuity, are securely crimped, and not damaged.

I reassembled the TIPM for now. Looks like I’ll be looking at different TIPM repair services and go with one of them.

Wish I could figure out what sends the ground signal to this wire, which then energizes the relay. Maybe with that info, it would help me be able to diagnose further.

You're most welcome, at least you understand the circuit and where it fails to function.

Here's a crazy thought...

I must first warn you that I'm an advanced procrastinator and have been known to promote these advanced procrastination skills to others.

On the schematic, it shows the fuse for terminal 86 is connected to the "Hot w/Run relay energized". I would prove this is true with your truck by confirming the 12VDC disappears when the ignition key switch is set to off.

If that circuit is switched with the ignition switch, we're good to go. Otherwise, we should have further discussions on this idea.

I would add a switch to the brown/light blue wire that would allow a ground connection for relay terminal 85. This would allow immediate satisfaction to that circuit, activating the fan and your comfort while driving.

Make sure to not cut the wire near either end, leaving enough slack so that it can be neatly reconnected at a future date {} with an inline crimp lug or soldered with heat shrink.

This would restore the ability to use the AC in your truck until you can find a cost-effective solution.

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[dannyloski]

Well the TIPM was sent out to MAKS TIPM Rebuilders, they inspected it and thoroughly tested it and determined that it’s in perfect working condition. So if it’s not the TIPM, what could be the issue? I’m out of ideas, any thoughts?

 

[dannyloski]

A member on one of the Facebook groups shared the electric fan’s wiring diagram (see attachment). @RamDiver any insight?

 

[RamDiver]

For this process to work more efficiently and effectively, we should make a plan together before you jump to conclusions and spend money on unnecessary tests or parts.

I would advise caution using any schematic that cannot be confirmed as the correct one for your vehicle. Besides wasting our time, it could promote a catastrophic and expensive failure.

If we use that schematic, just for clarity, please confirm that you are looking at 'Relay - Radiator fan High'.

The BR/OR wire connected to relay terminal 86 should have 12 wrt to chassis ground.

Measuring across the relay coil #86 positive lead, #85 negative lead should show 12 VDC when the relay is enabled.

If you successfully measure 12 VDC wrt to chassis ground on terminal #86 but don't see 12 VDC across 86 & 85, the rad fan control signal ground is not getting to the relay or not being generated by the rad fan control module.

Before deciding that the module has failed, I would carefully test everything from terminal 85 all the way back to the fan control module, including any wires, connectors and/or PCB traces.

With the positive lead on 86, touch the negative lead on 85, then the other end of the BR/LB at K175 and then as close as you can get to where that connection meets the Fan Control Module.

Don't assume that any wires, connectors, or PCBs are conductive, prove the entire path with your multimeter.

If anything isn't clear, please ask.

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