What you need to do is get it diagnosed properly first. That is good that your local Indy did not charge you, good to know there are some ethical techs/shops out there. You need to find a shop that specializes in Volvos and has the ability to pull that code out of there.

You can test the fan but that might not give you a difinitive answer. You say it works for the first 10 seconds or so, does the fan blow at this time for the first 10 seconds? If so you could probably assume that it is OK, however it may be on its way out and is pulling more current then the system will allow for so it posts a code and shuts it down. It could be an internal fault in the power stage causing the same problem. It could also be some other problem like a temp sensor malfunction.

To test the fan you would need to take a look at the schematic and supply it with power and ground and see how it works. You might also want to have it all hooked up and fire the car up and see if you have current at the fan or not. See what is really happening in that first 10 seconds or so.

In looking at the schematic for a '98 S70 the blower fan is hot all of the time and the power stage controls its path to ground. If you jumper the blue lead to the black lead at the power stage it should provide ground to the fan motor and it should run at full speed. The two pole connector at the power stage with two fat leads in it, B1 and B2.

Mark