Quote:
Originally Posted by Mike in AZ
With Air Conditioning OFF......
You are only on the temperature driven logic for the main fan.....
1) Fan goes from off to low speed at 226F (rising) and shuts back off at 219 (falling).
2) Fan goes from low speed to high speed at 235 (rising) and back to low at 226 (falling).
With Air Conditioning ON.......
All temperature logic (above) applies, PLUS.....
You are also operating on the A/C system pressure logic.
1) When system pressures in the A/C require airflow across the condenser, the fan will go to low speed. When system pressures rise to a higher level, the fan will go onto high speed.
2) Not all SSRs act the same. There may seem to be some variability in the pressure switch points, but it is really just the freon charge in the system, cabin blower speed, outside air temp, inside air temp and vehicle speed.
3) At speeds above 35 mph, the A/C system pressure logic is disabled and you are back onto the temperature logic only.
Hope this helps your understanding....
Mike
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I know there is enough thread on this fan issue for Mike in AZ to weave a Navajo rug, but here goes: Yesterday I picked up my 05 auto from the local tranny shop following an install of Greg Ducato's convertor and Servo. They had the battery disconnected a couple hours during the install and had it out for a test drive already. The fan was operating perfectly before, but now has no high speed. When I punch the AC button, it goes from slow to off. There must be a fuse or relay for me to check first. Where is it?
