AC Fan blower quit working on high

[totalpackage]

The drawing is not correct. Even engineers can make mistakes! The blower motor wire labeled PPL for purple color should be wired to the common terminal of the relay (where the dark blue wire is connected).

The dark blue wire then connects where the purple wire is currently connected.

That is why you have no high blower speed.

Larry

Thanks, Im not sure i follow. The diagram shows it being controlled from 1-3 fan speeds. When switched to 4, it energizes from orange which picks relay and the red and ppl connect.
So yellow is fan speed 1, Tan is fan speed 2, LT blue is fan speed 3 and orange is fan speed 4.

 

[PG01]

@retiredsparky i understand you are an electrician but that makes no sense because basically a resistor is to resist, slow, or stop something, so full power to the fan on high, less on med/high, less on med, etc....which is why when resistor girs bad you lose med/high or low or both...high always works.. im no electrician tho.

 

[east302]

Here are the diagnostics for a 98 with no blower operation on high. The key, it seems, is to see if you are getting 12v to the relay from the control panel, and 12V on that high speed relay at A2 and to see if the relay is switching over.

 

[Motown 454]

On my 99 I bought new controls for the dash. When we Changed it it ended up just being a bad connection from the Harness to the switch, check it out it worth it. We Clean the connections and put dielectric grease been working for years

 

[totalpackage]

ok, wow all this time and ive seen multiple post on forums on a connector melting but thought it was above or around the resistor and relay. To the right of the blower is a connection wrapped in insulation and it had melted. Im guessing due to the current draw of the old fan. Anyhow here are some pics the red wire would not let the current thru but you could still read voltage. During the load when on selection 4, it dropped to zero. Unplug the fan and it would go to 12vdc. All fixed now and that sucker blows like a new girlfriend.

 

[east302]

Good deal, glad you got it sorted out. Thanks for the update.

 

[Motown 454]

Great news, it sucks having something like that driving you nuts.

 

[totalpackage]

Yes, it drove me crazy. I will say i measured the old fan current draw and it pulled an average of 27.8 amps upon startup running steady at 1amp on high. The new one had an average of 12.8 amps upon startup running steady at .6amp on high. All measure with a digital fluke meter. Had to record the tests because you could not visually see it happen on the meter upon quick startup. This was all tested while engine running and battery at 13.5vdc.