Rad cooling fan

[jenkinskg]

Radiator cooling fan not turning on by itself.
So temp was high, noticed fan did not turn on, even when ac was on.

Went into Vida and was able to activate fan directly, but not activate through the ECU.
The single wire to the fan must be ok, but the ability for ECU to turn it on is not OK.

Any suggestions appreciated!

[Botbasher]

Bad temp sensor??

Did you look at the actual temp while in VIDA??

Cheers!

K "steamy" S

[jenkinskg]

was late last night when I activated fan, will look at all parameters tonight
New temp sensor came with the new thermostat

[oragex]

Depending on the brand, some sensors may not be reliable. Did this happen after replacing the thermostat unit?
Another thing that can go bad is the fan controller, the metal box located right on the fan

[Botbasher]

Yeah... but that doesn't mean it isn't bad.... just means that it's new.

We have issues like this often now with the new PLCs (Programmable Logic Controller) that we are implementing in our equipment. They have an option for a "manual" (push the button and things come on) control or the PLC can do it automatically based on sensors or other input.

The techs think that if the output is working that everything else must be OK. We find quite often (although not possible here) that they put the thermocouple in backwards causing it to read -F and shut down once out of parameter. They hit the manual button to turn on the heaters and "oh look.. it draws amps and heats.. must be working OK". We then go to a temp read out screen... see it's reading -75F in a kitchen environment... they feel silly (because it's really hard to install with bright red/white wires to simply trade out)... swap the wires and magically it all works better.

That won't fully explain your situation, but if you can run it with VIDA, then you know things are working. You just need to determine why the ECM isn't turning it on and the sensor output would be the first place that I would start my process.

Reading the sensor in VIDA makes the process simple to start the troubleshooting!

Hope it's a quick find!

K "troubleshot!" S

[jenkinskg]

Thanks, will try to get to it today, I agree with you, but why can't ac turn it on when Vida can?


Whole story, head was just done, new thermo housing with sensor installed.
Problem is head was done because last guy overheated it, so problem was a problem before I got it.
DIM repair may solve it also, it causes glitches on can bus and also may items stop working when dim is removed.
door lock, windows, etc etc

[Botbasher]

Thanks, will try to get to it today, I agree with you, but why can't ac turn it on when Vida can?


Whole story, head was just done, new thermo housing with sensor installed.
Problem is head was done because last guy overheated it, so problem was a problem before I got it.
DIM repair may solve it also, it causes glitches on can bus and also may items stop working when dim is removed.
door lock, windows, etc etc

Because VIDA bypasses the set of parameters that turn the output on. Think A (AND) B=C. When A is on... C=0. When B is on... C=0. But when A and B are on... C=1. You could also have an OR statement.. A (OR) B=C... A=1B=0... C=1 A=0 B=1.. C=1 ... then there's NAND NOR... OK OK... you get it!

Now you go into VIDA and say... C=1. Output comes on no matter what the inputs are. Direct control. You can turn the blower on high even though the knob is not moved, correct? You can turn the dome light on without opening the door, right? It can be dangerous, so some outputs need certain parameters met before operation, but for the most part you are simply forcing the output on without any regard for the inputs.

Yes... DIM repair may solve several things unknowingly. When I disconnect my DIM, the AC blower turns on often. The interior lights turn on. The dampers all open and the rad fan does turn on at times. Conversly, when I disconnect the CCM, I lose my door chime and my headlights like to come on. CAN-bus is a goofy things as I am learning. All houses must be in order to assure proper operation.

Good Luck!

K "logical" S

[Danpaco]

Have a look at the purple data wire connector (not sure what it's called) from fan to ECU. Mine had failed and caused hours of searching for the cause. I ended up cutting out the Volvo connector and added my own.

[jenkinskg]

I traced the purple wire and see it going to airflow sensor, probably a y to ecu etc also

Printed color schematics today looks like pin on ecu connects or should connect to fan violet wire

[jenkinskg]

did a few other things today.
Moved some wires around, and ran it a little.
Fan runs slow while in ac mode.

SO I guess dim will resolve regular fan functions, I will update post