1993 850 A/C Fan Problems

[Glen]

2 years ago my automatic climate control box burnt up a processor. Bought one from a salvage yard. After installing the A/C worked OK but the fan would blow very weak at start up then get stronger as I drove. Now the fan has quit and I have a code 418 in the computer. Pulled the fan and tested it with 12 volts, it works fine. The closest dealer is 2 1/2 hours away so I really want to solve this on my own. Has anyone had this code in the past and what was the final resolution. I am thinking I have a bad fan control module which burnt up the original control box and has now either quit all together or has caused the second control box to fail.
Any help or guesses would be greatly appreciated, normally I'd just change parts until I fixed it but at $750 for a climate contol and who knows how much for a fan control module this could end up costing quite a bit.

Thanks for any help you may be able to offer.

[Glen]

Further to my earlier post I found a fan control (new) through a parts outlet on the internet. After replacing it the A/C works as normal.
Code 418 is no control signal to the fan control module, when this code is present it presets the Automatic climate contrl fan speed at 28% hence the poor fan performance since I put in the replacement ACC box. My suspicion is that the fan module burnt up my original ACC box and I was very lucky it didn't burn up the second one. When I say burn I am speaking literally.
My recommendation would be if you ever replace the ACC Box also replace the fan control module, at $100 it is cheap insurance.
By the way I also bought an ACC box from a guy parting out a 1995, if you have a need for one contact me for a price.

[matthew1]

Thanks for the info, Glen.