I have a 1985 300td turbo. The climate control isn't operational and I want to take it to a shop to fix it. I know if I jump the low pressure switch, the compressor kicks on. I also believe the monovalve is shot as it blows the same no matter what setting it's on. I am pretty sure the push button controller is OK. That is all the info I have since I am not qualified to fix this system.

Does anyone have any advice on how to handle this with a shop? Should I convert to the new freon or try to have it fixed with the original freon? How much should I expect to pay in a worst case scenario? Are there any ripoff or lack of knowledge issues I should look out for when dealing with a shop?

Any help would be appreciated. I searched the forums already and couldn't find anything appropriate to my situation.

Thanks,
Chad