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1 gen trooper cabin air blower and AC

188 Views 6 Replies 5 Participants Last post by  1989trooper
1990 trooper.... the air flow from blower is much lower than I remember when purchasing it it 1989. this is next issue I want to address on my restoration journey.

I expect there is some foam filter on blower intake side but can't find fact, still trying to figure out how to remove blower to clean fan blades. ...........any help in increasing flow appreciated.

the factory AC was always anemic and thinking of other my mods that will make it more efficient.
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My 1983 P'up shares the same system (in fact, some of mine was pulled from an '89 Trooper). I have the same issue, but have not yet found the time to troubleshoot.

There's no foam filter. I doubt the blower blades are the issue, whether dirty or not. But the blower housing is on the far right side under the dash, with a bowl-shaped bottom. The flange around the top, and the motor itself are held by 3 Phillips head screws.

It seems to me there are three possible causes for the blower output to be low:
  • Voltage drop due to deterioration of connectors over the years (any connectors in the circuit).
  • Failure of the fan speed control resistor assembly. The speed control rarely fails at the "High" setting, because it bypasses all the resistor coils. They normally fail on lower settings that use the coils.
  • The fan itself (worn out)
My first test, if I get around to it, will be to connect the blower wires directly to a 12v (fused) source. If it blows normally, I'll assume it's either the connections, or the speed control.
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the factory AC was always anemic and thinking of other my mods that will make it more efficient.
Regarding the A/C itself, there are no shortcuts when dealing with A/C. There's no magic in a can, so don't even be tempted to use that nasty stuff. It makes things worse.

Are you using the original R12, or has it been retrofitted for something modern?
philips screws on the fan housing from the bottom of the passenger side foot well. 3 or 4 screws and the fan will drop down. see if the squirrel cage (fan cage) has any play in the shaft. might want to oil the bushing (no bearing) on the bottom of the fan housing. Sometimes a small hole can be drilled to allow oiling access. Also over time, water can get into that bushing and cause corrosion and resistance.
AC was updated throughout the decades with new and latest refrigerant. I tried removing the 3 or 4 screws at bottom of blower motor but they did not come out, only spun. I figured there was a nut moving on other side.....not sure I was turning the right screws. I'll look again. the airflow is too low to do much if I install new compressor so want to get more flow first.

Is there any filter element for blower?
Is there any filter element for blower?
No there is not, we have to raw dog that unfiltered air.
i had problems getting enough airflow for my A/C. The levers would not shift to max.
The shop I took my Isuzu to specialized in auto AC. The mechanic didn't want to pull things apart under the dash because it would be difficult to find replacement parts.
However, the mechanic suggested a solution. He was able to wire in an xtra switch that boosts the power to the fan directly from the the battery which allows maximum airflow. It was night and day different after the upgrade. I now enjoy driving during the summer and the heater also blows hi as well in the winter.
I have a 1989 Trooper with the 2.8 gm motor . Manual trans.
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