Well I can’t thank you for all your help Gerard and VTL. I found the break in the purple wire.

All is well now

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

vtl wrote: 22 May 2026, 04:54 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?

yes, a signal tracer or fox and hound, can trace signal along its length to the break. $25 amazon.
https://www.amazon.com/VDIAGTOOL-V210-Automotive-Electrical-Circuit/dp/B0D17ZL83R/ref=sr_1_7?crid=2XYIKYAJ11OD0&dib=eyJ2IjoiMSJ9.fo3dGVggLDIHOboczr-mUD ...

This is on my wife’s 376,000 mile 04 XC70.
I replaced the original radiator (blue box actual Volvo part), because it got a hole, replaced the heater core for the same reason.

I noticed it running hot on a few occasions over this past winter. Now that temperatures are warmer, it seems to want to ...