Volvo: 1992 Volvo 940 GL, volvo 940 gl, 1992 volvo 940

Question
My 940 overheats in stop and go traffic. I also notice the electric fan is not coming on. How do I troubleshoot whether it is the fan, relay, or some other problem?

Answer
Richie,
The relay is in front of the battery , the large plug with the red and green wire powers the fan. Unplug it and supply power to one terminal at a time. (High and low speed) That will show whether the fan runs or not. If it does then I would try a new relay.