When I have the heater fan turned on, I noticed that the fan level drops every time I get off the accelerator. I have tested the alternator and while running it puts out 14 volts, so assuming it is somewhat ok, but not sure. I have a separate problem where when the a/c button is pressed the fan and unit cylce on/off until I turn it off. Assuming that there is another related issue somewhere causing this.

Ideas to help solve this problem? Should I need another alternator, climate ecu.. suggestions on the best model of alternator would be appreciated.

 

higher rpms produces more heat , consequently fan clutch senses the heat and allow the fan blade to rotate faster

that is a good alternator since you are measuring +13.5v when all systems are running

which fan and unit are you referring to ? heater fan ? auxiliary fan if you have one ? unit .. meaning compressor ?

 

By fan I mean the fan that runs the heat/ac inside the car. The air coming out of the vents cuts in half when the accelerator is lifted and then levels out.

When I press the a/c button, the entire unit, all buttons and screen blink as the entire power cycles on/off within the climate unit in the center console the fan blower motor also cycles on/off. When the car was purchased that only happened when the a/c button was pressed. Then it started happening whenever the unit was turned on. Now it is back to working except when the a/c button is pressed. All these weird problems along with flickering dash 'back' lights on the tach, speedo, just lead me to believe that there is something electrical happening. Symptoms go from severe to almost normal.

Example, had not driven car in weeks, got in and it was back to running horrible, almost like limp mode in 97's. Called Toyota and took it in 2 hrs later. On the drive there, it started running properly again. Hours later the techs could find no problems of any type. Learning that electrical issues are no fun and even after multiple trips to Toyota we're still hunting for the problem.

 

but I have no suggestions on where to look. Good luck, keep us posted.

 

look at the ECU caps, ECU is under the driver side carpet, pull it out, look at the capacitors for any leaks, sounds like you might need a rebuild on that.

 

If you are talking about the main ecu for the entire car, I had that done a few months ago. Is there a separate ecu for the climate system?

 

no i was talking about main ECU. have you relocated your driver side wheel well harness? if not, check the wires there. from there on you're gonna have to start checking the Resistor and Transistor for the blower motor. But first i'd check with a known working climate control unit. i've never seen the issue you're saying where it turns on and off, that sounds like it's not getting enough power or something weird. check the fuses too, there might be a fuse too small or something.