Steveh4263

iTrader: (1)

I have a 87 GTA. The air from the blower motor doesn't seem that cold or strong from the vents. Car was converted to r134a, Is there another blower motor from gm that is stronger and blows more air? I read the forums and seen mention of a stronger blower motor from another gm vehicle that connects directly to the same place as the oem blower motor does. Thread didn't mention other gm car that had the compatible blower motor though. Anyone know of this gm car with compatible blower motor?

dixiebandit69

Is this the factory blower motor? If so, it's getting old. Also, the wiring/ switch/ connections feeding it might be losing a lot of voltage. Make sure that you're getting at least 13.5 volts to the motor with the switch set to "HIGH".
Also, try taking it out and looking into the HVAC housing; there's a good chance that it is full of leaves or pine needles (depends on your part of the country.).

Check these things out first, before you go spending money on a new blower motor.

Abubaca

iTrader: (3)

I have the same issue, though I haven't done any trouble shooting yet. For me it definitely seems more of an air delivery issue. The AC is fine. It's the blower. I'll follow along....see what other people say too, but good advice on the voltage and physical blockages.

1989karr

Try feel the accumulator if it is cold top to bottom after the system has been running for a bit. if not, add a bit more refrigerant.

Also, more air flow helps... I noticed massive ac improvements when I installed LS fans. They are shrouded and pull more air through the condenser which helps cool it better / provide better ac.

LiquidBlue

make sure your vent door is closing all the way. otherwise you're letting engine heat into the cabin.

tom3

Take a look at the pressure switch on the side of the accumulator. When you unplug the wire there is a screw adjustment in the switch. You can adjust the cutoff to a lower pressure and temperature and get a bit more cooling. I take mine down to about 20 psi with no problems. And be careful not to overcharge the system, that r134 is a bit different in an R12 system. Compressor should cycle some.

Fast355

iTrader: (2)

I used a 99 Tahoe replacement front blower motor on both of my G20 vans. The G20s used the same blower as a F-car with ac. The Tahoe blower has a rubber seal, rubber isolators for mounting and the wheel is the same size as the older ac gm blower. Has a more powerful motor. Vans definitely blew a lot harder after the swap but be careful of old wiring.

Before my laptop battery rudely went dead, I was about to describe what needs to be done to the wiring. After swapping blowers, it started to melt the old high blower relay connector on the old 1983. I converted both of the G20s over to an Express van blower resistor with a built-in high blower relay. I also rewired both the power and ground to the blower motor. The high blower wire on a typical GM is fairly undersized if you plan to run high fan speed for very long. In fact, I recommend no more than 15 minutes of high fan speed operation if the power feed is unmodified. Here in Texas on a hot day that is not an option. I grabbed an Express van blower resistor and matching connector. I removed the old resistor and old high blower relay. I traced the wiring back. There are 4 switched settings, each has its own power wire for the corresponding speed. On the lower 3 speeds the dash switch powers the blower motor through the resistor for the speed in use. On high speed the switch activates the high blower relay. The express van resistor portion that pokes into the ac housing is a little larger than the typical older style wire resistor. I had to open the case up slightly to match. Since the early express van used a resistor that was smaller, the supplier was thoughtful enough to include a templet to trim the housing. I trimmed the housing and mounted the resistor, then ran the 2 wires from the blower resistor toward the blower motor. I cut the connector off the express van resistor and installed two weatherproof spade connectors. I then ran the large gauge positive wire to a 40amp circuit breaker that I connected to a new junction block that was fed from both the battery and the alternator through fusible links. I had previously replaced the junction block because they had a habit of melting when the alternator was replaced with a higher amperage unit. The heavy gauge ground wire was connected directly to the alternator mounting bracket given its proximity. Now for the funny part, between 1983 and the 2006 Express wiring diagram, they used the same color wires for each speed. I have since found its almost universal for GM to use those colors. In a nutshell all 4 wires go to the matching colors on the blower resistor connector. The end result of that work is the blower motor now receives near full system voltage on high fan speed and blows even more air. The old blower was half of the equation, the wiring was the second yet equal half. At 25 amps with ~10 ft of wire in the high blower circuit (remember it includes the ground side as well) it required at least 10ga (I used 8ga) power and ground wires. With the system at 14.5 volts the blower motor is receiving 14.3 volts on high fan speed. That is as good as it is going to get and far better than it was.

2006 Express


1985 F-car

LiquidBlue

Interesting stuff! Was the Tahoe a drop in replacement, or did you have to modify mounting in anyway? Out of the many manufacturers available for our blower motors, we should be able to find one that is publishing power draw and make a comparison.

Here is a 1990 Camaro VDO - PM 137
https://www.rockauto.com/en/moreinfo...=1099&jsn=1099

1985 Camaro (PM 140)
https://www.rockauto.com/en/moreinfo...=6916&jsn=1305

1999 Tahoe VDO (PM 149)
https://www.rockauto.com/en/moreinfo...sn=993&jsn=993

350Iroc89

iTrader: (3)

Which way to turn the adjustment screw? What's your adjustment method? I converted to R-134 too and have been trying to maximize performance. The system seems to cycle a lot. The most effective thing I have done is turn my fans on sooner via a new ECM chip which keeps engine and underhood temps down. Coolant stays right around 180 in town with the A/C on now though it does heat up on the highway a bit.

Fast355

iTrader: (2)

R134a will never cool very well, even in systems designed for it. R152a, Duracool or Envirosafe Industrial R134a substitute will all cool noticeably better.

1989karr

I dunno... My 134a goes down to about 38. I calibrated the thermometer too to make sure lol

Fast355

iTrader: (2)

I get that at idle with a dual evaporator system in 102°F and 40% humidity. Going down the road it has gotten down to 29°F before the compressor cycles.

1989karr

Mines just a stock converted system


29 sounds delicious!

LiquidBlue

Me too at idle (35.7) , temp same, but humidity is higher, running r134a. All factory except the refrigerant, oil, and orifice. Don't know what it gets going down the road, T-Tops always off, busy driving! Maybe I will have the wife check for kicks and grins. You didn't answer my blower motor question above?

https://cimg3.ibsrv.net/gimg/www.thi...c6ba60a88e.jpg

1989karr

My 38 is at idle after a few minutes right after start up/

So if you get 35 it probably goes to like 32ish on the highway with the extra air over the condenser. My S10 goes to 32... on the stock setup / mechanical fan n around town driving.
I think anything lower and the stock system would freeze though.. I get frost on the accumulator even in the hot engine bay when I open the hood.


Cold air is delicious!

Fast355

iTrader: (2)

Sorry I missed it some how. IIRC, the Tahoe blower was a direct bolt on from memory minus a couple of the bolt holes. I had to twist it slightly to line up the cooling air tube. I used some speed nuts pushed over the blower case to securely mount it.

dixiebandit69

THANK YOU for posting this and verifying my thoughts!

I asked a question on here about using the Express Van relay/ resistor as a way to update and clean up the HVAC wiring, and people pretty much said I was stupid for trying, because the factory setup worked just fine.

Fast355

iTrader: (2)

The Express van one works better than the OE ones. I burned several of the stock high blower relays out on my old 83 and that was with the stock blower motor. After rewiring the blower the motor had near full system voltage. The Express van one looks cleaner and handles higher amperage since it too has a more powerful motor. The Express van front blower draws nearly 30 amps at startup.

As installed in my 97 Express.

LiquidBlue

I did look for manufacturer specs for amps/watts, that sort of stuff, but they only seem to publish 12V needed. Would be nice to have that info available.

Don Christensen

Wife's 89 Formula has a similar issue. The system cools very well, but just not blowing much air. I checked and at idle there was only 10.94 volts at the blower. The relay was burned, as was the wiring. Replaced the relay, and will next go in and replace wiring with larger wires & new connections.