Dear all,

Hope you are doing well.

My engine rear blower is only working in high speed mode and maybe someone can help me. I’ve been looking for info but run out of ideas.

Problem is the following: when setting climate control at red (maximum temperature) and fan speed **** to 1, fan runs at high speed, which should not. Of course, if speed **** is at 2 or above, it runs at high speed.

To diagnosis, I tried the following:

• Tested the relay by shorting terminals 30 and 87 for high fan speed shorting terminals 30C and 87C for low fan speed has been successful.
• Removed the resistor and its seems OK, but ….. measured about 5 oms at around 18ºC room temperature, and found some info about a possible reset, but the truth is that I have no idea what it should measure or how to test it.

I will very much appreciate any help or ideas.

Thanks,

 

I would start with this troubleshooting diagram.

https://www.bergvillfx.com/porschehvac1

 

Thanks Rob,

I did review that great information before asking, and at the end just come up to the conclusion that the fan was not working as it is supposed to do.

Anyhow, this afternoon tried one thing and worked: changed the relay for the on used for the A/C, which is the same, and immediately resolved the problem.

Problem solved and lesson learned!!!