Most of the time, the 'only runs at high speed' symptom indicates a bad resister in the heater box. The switch is probably OK. Fred
Thanks Fred. Any further clarification on this problem? (Where is this resistor? Is it easily replaced?) BLES
I do not know what vehicle you have so follow the wires from the fan switch in the dash and you should be able to locate the resister assy. It is normally a small bakelite plate where the wires from the fan switch plug on to. Usually mounted on the heater box with 2 screws. If you find it and dismount it from the heater box you will find the resisters on the other side of the plate from the plug in. Usually the resister/s will be open so current can only flow at full speed. Best to check with an ohmeter, but can usually be seen with a visual inspection. I am only fully familiar with the suzuki/mazda CarryVan/scrum so cannot tell you where to look, only what I know as general knowledge. Don't know of it's availability so if it is bad, you may have to make a different unit work from a junkyard or something. Most all older vehicles use the same basic system for fan speed control, not so sure of the newer ones with all the computer controlled crap on them as I retired in 1990. Fred
