Yesterday I pulled out my dear diesel. I put on the AC to see how she was doing. In a minute or so she blowing cold. I went on a small cruise and had the thermostats set on 62 degrees . Cold condensation was forming on the lower windshield. AC was working great! Engine temp stays a tick over 80c. I came home shut her down and the low speed auxiliary fans stayed on with engine off and key removed. I figured it might have been hot so I left to go to the store for about 20 minutes.

When I returned the fans were still going. I looked around couldn't find any broken wires. I almost disconnected the battery, when I went to the main fuse box near the firewall. I removed a 30 amp breaker and they turned off. This am I installed the breaker and they went on with no key again. Any one know where I should start? I read about Temp sensors going bad. But most of the posts were about gas W140s not diesels.