I fixed mine this weekend. Heater - AC fan blower problem. The vehicle lost its lower or medium fan blower speeds, appeared dead until i cranked it up to the high setting. ----- I have 2001 Mercury Mountainner 5.0 V8, with automatic climate control. It uses a large transistor as the control element mounted in same type gizmo as would be the resistors. Resistors are on the vehicles without automatic temperature control, and having a dash selector switch with detented positions, about 4 of the speeds. The automatic models have a temperature readout, and red and blue buttons to raise or lower the target temperature. ------ You can look at the various Youtube videos for the prepwork of making room for this job, most models explorer or mountaineer similar---- Location: passenger side firewall and fender area of engine room. --- So, after moving/removing the various cootermounts, (Air box and hose, Criuse Control, Washer and Coolant tanks) one can then get at and remove the blower assembly. On mine the control element (on with a plug and two screws) was right below the blower. One must remove the blower to see what alls going on in there, such as dirt or corrosion buildups. Such would have to be cleaned to promote airflow. Be careful removing the plugs. If severe corrosion has occurred these might be stuck or damaged. Mine came off and were not damaged. ----- I took the control module (AKA blower resistor) inside to the workbench, removed the circuit board (was on with two screws) looked with a magnifier and found a corroded spot, after cleaning that, found a break in the copper trace. I bared it, tinned it (a soldering term) and then soldered a thin 28ga buss wire there to fix. Cleaning it again to remove rosin flux is in order. Then after cleaning and drying the board with some alcohol, i sprayed on two coats of clear varnish onto the solder side (to prevent future corrosion) I also tested the transistor and found it to be OK. This done with a digital meter, that has a "diode" test position on the selector. It tested OK. You can find online tutorials for all these items. If not comfortable with electronics, take it to a good electronics dude who can check it for you. Of course it would have to be a hacker kind of guy, as this module is not in the books anywhere. --------------I went a step further and disassembled the blower to clean, check and lube it (again not a job that can be done by anyone. I've been doing it a long time. If you break it you bought it.) (The end plate is staked; which means you have to unstake it. When finished you to have to restake it together. There's only one chance to do it right. A do-over will break off the tabs. Also the brushes upon reassembly have to be held on with string or a tie wrap. When in proper position you can then cut each string or wrap and pull it out, leaving the brushes snap to. -----Commutator wear will be apparent , but so long as there are no gaps, it'll still run. Of course real severe wear or broken brushes are a no go. That calls for new blower. Do not put new brushes on an old commutator. bad bad -------- All went well. I tested the blower with a spare battery. --------------- Put it all together today. I put silicone connector grease in the plugs to prevent any future corrosion. ------full function now restored. I have all the blower speeds. Saved somewhere around 160 dollar, hoping to get two more years out of it.
