HV battery cooling fan fault and fix

Do you have any code to start? Apparently it could be quite a few thing, so rather than poking in the dark, get some codes. I have a second Prius now and I just sorted out a red triangle issue recently. Wasn't as easy as the fan.

 

I second that, read the code or codes the VSC ECU is reporting.

 

Recently went to local repair workshop and there was nothing came up in code reader as warning lights disappear after some hours and at the time when they try to read codes nothing come up.

 

Look, I'm a bit lost, you have VSC light on (only) and you tried to fix it with the HV battery cooling fan? The symptoms we (I had) was red triangle+ABS+brake control+brake lights on. Apparently I don't have enhanced VSC in my car so the VSC light did not came on. So I presume you should look for solution some other topics as well. Just for the record, I have a second Prius, 2003, I bought it with the mentioned lights on with the hope it's going to be the same as the first one. It isn't that simple. I had to learn it on the hard way. However thanks for all the help and support what I received from this forum, I getting closer to the solution. Even though I had to purchase proper scan tool to find out the real issues.
Without exact codes, I also just doing random checks here and there, sometimes with luck sometimes without it. In your case I would definitely try to capture the fault. By the chance do you know what scan tool the garage used to diagnose your car? It is quite crucial as well.

 

Hi All,

I need to update you as I have now soldered the broken brown wire in the connector and I have driven the car around 450 miles and this warning light has not appeared again and it looks like that like most of other friends this was due to the broken pin for the brown wire due to corrosion.

kind regards,

 

Very nice, I'm glad you've done it.

 

I'm having this exact same issue.

However I'm in the US and this connector I believe which is the one you're showing is on the other side.

Anyways I can't seem to figure out if this is actually the fan or this connector.

Looks VERY similar to what happened to yours though.

I cleaned this connector with electrical cleaner and re connected but the same warning light for this fan not operating came on (P0A84)

Will try to get some clamps tomorrow and try an test the fan itself but I think my issue is the same as yours was/ is

 

Dude I was just gonna reply to you on reddit and was gonna share this site address

 

I'd get some clamps, I had a good mechanic to s clean up and splice the wires after I showed him what I found.

 

That's pretty funny.

I'm trying to find the part number for this terminal to see if I can just replace it.

Wiring is something I've never done before

I'll pick up some electrical claps tomorrow and test the fan then go from there.

 

Nah just cut off the plugs and butt splice the 2 wires. Color to color. You can heatshrink the butt splice if you want to get sexy. Requires a heat gun.

You can't out board test the fan it uses PWM for fan speed.

Dont bother testing just butt the wires and see if it works. In READY the fan is on all the time on speed 1 to circulate air in normal use. You cant hear it in the cabin its turning so slow to leave the car all aprt so you can see the fan turning for a test. Put the car in ready then fan should come on.

 

Just tested the fan before reading this using clips and using the 12v battery as power

Works fine.

So I went out and got some of those connectors you slide the wires into and then just crimp them down.

Oh those are butt splicers

Good ol butt splicers.

Worked

Job finished

HV battery happy

Cheap as can be to fix

 

Old thread but happy to confirm that the OP's diagnosis and fix was spot on. Had exactly the same issue and followed the steps in the manual to find fault but didn't see the plug and socket in the cable linking the HV Battery ECU to the Fan control Unit and Relay over the other side of the car. These cables provide trigger power to the relay, pwm signal to set fan speed and detect the voltage at the fan. There are also three other wires in the plug not connected to anything! All of mine were corroded so I cut out the plug and soldered them together with heatshrink, tape and cable support to protect them. Perfect now.