Cm870 overheating issue? Maybe

[Evotrucker]

(05-09-2019 )Chamberpains Wrote:  You have a cm870. You can probably just cut and splice into the fan solenoid wiring and run a toggle switch to the dash to "break" or "open the solenoid circuit to get a manual override. It shouldn't throw a code. To test this, simply unplug the solenoid with key on and see if your fan engages without throwing a code. Volvo may be different and have some strange dash code.

Cm871 and newer throw a code doing this. They get around this problem by plumbing in a 2nd solenoid down stream or right after the factory solenoid and have it isolated to its own electrical circuit.

As far as your codes, I would clear them and see if they come back. They only happened 1-2 counts "times". They all could be a 1 time blip. I wouldn't throw a harness at the truck for those codes and counts alone.

Low coolant = low coolant - add coolant

Loss if power without key off = low voltage to ECM with the key on - probably low batteries while cranking or possibly bad power wire connection.

Multiplexing codes often follow low voltage cranks or dead or dieing batteries.

Only reason why i wanna throw a new engine harness on the motor is because my luck hasnt been on my side as of late. Figuring the only thing its going to hurt, is the upfront cost but at least i wont have to be worried about when its going to go out but that might be something ill have to put last on my list.

Not concerned about the coolant being low since its never actually low, the tank has a broken clip on it so i just zip tied the sensor to it so it stays put for the most part.

ever since i was a kid, ive been frying anything to do with electrical components lol. ill have to find a shop to do it for me. I dont want to risk frying anything since ill be liable for it 100% :P.

I see volvo8873 gave me a good website but im not confident on doing the wiring my self but ill keep it so i can give it to others who are more able to do it.