Mischievous violet / purple radiator wire and a ECM-6110 (engine cooling fan relay - signal missing)

[- Pete -]

Early models had external relay, yours is molded into the module on the fan.

note, I snipped the violet wire near the headlight because I didn't want to back feed voltage into the ecm, disconnected battery too.
I don't like messing with the electronics on this car at all.

a coat hanger soldering clip helps hold the wires for soldering, i used heat shrink and liquid tape to seal the joint from moisture.
its an awkward position, you can only get one hand in there.

All very awesome and pertinent information! Thank you so much! Yeah, I planned on pulling the ECM and TCM when I run power through the wires to detect where the separation is.

And I know this is out of order, but, in response to your next message I do have power at the plug and nearest the fan. There is no signal power at the purple wire connector though. I have a short couple of video clips I can attach when I have a second. They display what the power at the purple wire should look like in a healthy vehicle versus what the power at the purple signal wire looks like on my affected vehicle.

[- Pete -]

Yeah I did see that FFM8 listing but in all the years I’ve been wrenching on Volvos never once realized there was a 2nd level to that fuse block! I’ll have to check on that. My fan is the style that has the power module molded into the rear by the way.

The "forever" fan, with brushless motor. Either that 60A relay is cooked, or ECM.

….. or the purple wire is toast at some point along its path …


Correct?

Thanks for helping me narrow it down. You’ve always been such a wealth of knowledge VTL. Truly, I want you to know you are appreciated.

[jonesg]

Vida is telling you its the signal wire.

[vtl]

….. or the purple wire is toast at some point along its path …


Correct?

Yeah... Could be. Not so long ago I found some mice feces on top of the engine. Weird... Our Volvo is driven the most in winter, would expect mouse to climb up Toyotas, which have been kept parked most of the winter. Anyways, I wondered what damage will follow. Some time later the CEL lit up, and a chewed up TCV wire has been found...

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These critters also destroyed wiring in my HVAC compressor unit, twice. I may start unplugging it for the winter: mice get attracted by heat from electronics.

[- Pete -]

Did you check the relay and fuse?

I looked for one that coincided with what was talked about out online and listed on the fuse panel lid but ultimately I found out that “the relay is built into the power module on the backside of the fan…” according to my research. Is that incorrect?

You have to remove the upper panel in the fuse box, the relay will be under it. A bunch of screws and fighting with plastic catches.

I don’t want to use too much force, I found the catches nearest the front of the box and all the screws, still feels like something is keeping it held in and going to break if I force it. The only instructions I’ve found for accessing the lower level pertains to a P3 V70.

Any other tips you could share?

[- Pete -]

Vida is telling you its the signal wire.

Yes that is what I feel led to also. Have not had enough time to use the tone generator to find the break in the wire yet. Also still trying to figure out how to access the lower level of the fuse box. Like you said, the relay should be fine if there is 12v at the fan plug (which there is). But I still would like to figure out how to get to that lower level. Found all the screws, found 2-3 plastic catches at the front of the box but still feels like something is going to break if I force it.

[vtl]

I don’t want to use too much force, I found the catches nearest the front of the box and all the screws, still feels like something is keeping it held in and going to break if I force it. The only instructions I’ve found for accessing the lower level pertains to a P3 V70.

Any other tips you could share?

Try this:



You may need to use zip-ties to hold catches released while you work them out around the panel, I forgot.

[vtl]

Like you said, the relay should be fine if there is 12v at the fan plug (which there is).

So it is either the signal wire or ECM. Could be oxidation in ECM contacts, too. Have you removed ECM? Need a tool like CTA 1070. If ECM is fried I would strongly recommend to find out why, or you'll burn the replacement as well.

[- Pete -]

Like you said, the relay should be fine if there is 12v at the fan plug (which there is).

So it is either the signal wire or ECM. Could be oxidation in ECM contacts, too. Have you removed ECM? Need a tool like CTA 1070. If ECM is fried I would strongly recommend to find out why, or you'll burn the replacement as well.

I pulled the ECM & TCM, put electrical contact cleaner on the prongs & the receptacles, followed by Deoxit, when I reinstall the 2 units I usually use the tool to raise and lower both several times to “clean” the prongs and their mating receptacles.

If there is some greenish tint on the prongs is that a coating or indication of oxidation?

I used a tone generator and I have pretty strong signal all the way from the purple wire’s termination at the fan plug all the way back through the fuse panel & it is weaker as it passes under the radiator, I somewhat lose the signal as I get within a foot or so of the ECM/TCM plastic box. I’ll take a video clip.

[jonesg]

with the battery disconnected, try an ohm test from the fan plug to the distribution box.
then from the box to the ecm, they should read very similar.