I believe that the common cause for this is a weak circuit breaker. The breaker trips after some time in operation, and then resets itself for the next cycle. If I recall correctly, there is an upgrade to a higher rated breaker that still provides protection to the circuit, but has enough capacity to allow the fan to operate for an extended period of time. The upgraded breakers use "loop-style" connectors, whereas the OEM breakers have a spade connector. This means that you have to change the connector ends on the wires to make them compatible with the new breakers. The spade style connectors are more prone to heat buildup and higher resistance than the loop connectors. There are two breakers, one for fan speeds 1 and 2, and the other for 3 and 4. The breakers are against the forward wall of the relay compartment to the left of the fuse box (if memory serves). Unless somebody else on the list has quick access to part numbers, I will update later this evening. Toby Peterson VIN 2248 Winged1 --- In dmcnews@xxxx, "fluxmcfly" <bfreyguy@xxxx> wrote: > Does anybody have an idea why my heater fan shuts off when running > the ac.I'll have it on high then it with stop blowing or will blow on > low,if you turn the fan switch to low then back to high it will work > usauly.It does this quite a bit but not all the time.Could this be a > bad switch or some type of power falure?Any thoughts would be > appreciated > very much thank you > > Brian bfreyguy@xxxx