Another A/C Question

[rdoine]

When, exactly, is the condenser fan supposed to be running in a 1988 911?

1. All the time whenever the compressor clutch is engaged?
2. Whenever the compressor clutch is engaged and the fan speed is set to high?
3. Whenever some temp sensor tells the fan to turn on?
4. Other?

I can't hear the fan running so I'm not sure when it is supposed to be on.

I have not had time to check that there is power up to the connector to the fan. That has to wait for this weekend.

I hate to pull the fan out unless I really have to do so.

Thanks for any feedback.

Randall Doine

[wwest]

It should be running, without question, when the compresor clutch is engaged. Otherwise, other times, I don't know.

[rdoine]

Thanks, that's what I thought. Now, I have to figure out why it does not seem to be running. Or, at least I can't hear it or feel any type of vibration when I hold the housing.

[tcar]

You should be able to hear it even in the car with the driver's window open. It's fairly loud.

If compressor is running, fan should be on.

I have one in my 78SC.

[dshepp806]

The bentley shows the condensor blower to be actuated by the Condensor Blower Relay (this relay being fired by the AC blower switch FROM the AC relay). Make sure those relays are good and that the the voltage is where it should be. Fuses would be a good start...

BEST!

Doyle

[DRACO A5OG]

Check fuse #2 if it is loose or worse shrank.

My fuse block needed replacing because of resistance which caused the fuse to heat up so much that it shrank or blew the fuse.

Replaced and no more issues, THANKS WWEST for the lead

[rdoine]

Thanks all. I'll check relays, fuses, etc. when I get back to town this weekend. Now that I have the system actually cooling, I'd like to see what happens with the condenser getting the correct airflow.

[gregwils]

I would jump it to the battery to make sure it's operational.

[rdoine]

Got back into town. Checked power to the connector to the blower. Definitely hot. Heated up my multitester wires. Pulled the blower out and turned the squirrel cage by hand. It turns but is not smooth at all. Could not get the motor to turn at all when power was supplied.

I'm going to take it to an electrical shop tomorrow and see if they can rebuild or replace the motor.

Bye the way, where is the relay so I can make sure a fuse is in-line before I put the blower back in. That is, assuming I can get it repaired.

[kuehl]

"Sometimes" you can spray some break free lube on the motor's shaft bushings to free it up, be careful not allow the lube to drip down to the brushes. "Sometimes" this works and buys you a few seasons.

[Barrpete]

Originally Posted by rdoine

Bye the way, where is the relay so I can make sure a fuse is in-line before I put the blower back in. That is, assuming I can get it repaired.

There are 2 relays for the AC and offhand I don't remember which is which, but one is in the smugglers box and one is on the fuse panel.

If your front condensor fan is fused it would typically be close to the fan itself. The factory mod used an inline fuse that simply plugged into the fan harness. If you don't have a fuse you should absolutely add one now since it sounds like your motor is circling the drain. Unfused condensor fans are a somewhat common cause of fires.

[86 911 Targa]

Originally Posted by rdoine

When, exactly, is the condenser fan supposed to be running in a 1988 911?

1. All the time whenever the compressor clutch is engaged?
2. Whenever the compressor clutch is engaged and the fan speed is set to high?
3. Whenever some temp sensor tells the fan to turn on?
4. Other?

I can't hear the fan running so I'm not sure when it is supposed to be on.

I have not had time to check that there is power up to the connector to the fan. That has to wait for this weekend.

I hate to pull the fan out unless I really have to do so.

Thanks for any feedback.

Randall Doine

Here's a little more help.






Note: The AC motor repair proceedures are about the same as the footwell blowers.

Footwell blowers squeaky, how to fix.

You may pm me.

Good luck,

Gerry

[86 911 Targa]

Originally Posted by 86 911 Targa

Here's a little more help.






Note: The AC motor repair proceedures are about the same as the footwell blowers.

Footwell blowers squeaky, how to fix.

You may pm me.

Good luck,

Gerry

And here is the circuit.

[rdoine]

Took the blower to the electrical shop and it is definitely "out of order". You can turn the squirrel cage but it is very balky and you can see burned wires in the winding. They are going to replace the motor and I'll install it next weekend. It's a lot cheaper than replacing the whole assembly, if you can even find them.

I WILL add a fuse near the connector.

Thanks for the pictures detailing the relays. Those will help once I get the thing back together.

[wwest]

Originally Posted by fred cook

I chose to upgrade the air conditioning in my SC. I live in South Georgia where we have many 95 - 100 degree days and a/c is really necessary. You can get decent amounts of cool air out of an early/middle year Porsche system but only with complete rebuild/replacement program. Just switching to a Sanden compressor will help and you will have more room in the engine compartment. Its lighter also. You will need the afore mentioned compressor, new barrier hoses (I made my own) an upgraded evaporator and probably front condenser. Unless you mount one of the rear fender vertical condensers w/fan, there is not much that you can do about the rear condenser. Also look at the Khuel vents for the center and ends of the dash. It's not cheap, you will get quite dirty and some of the bits and pieces are a pain to install. But, in the end, you will be glad that you went the extra mile! Good luck with your project!

"..but only with complete rebuild/replacement.."

I disagree...

In relation to the early Porsche A/C design when did inexpensive highly efficient radiator fan/blowers become available...???

Answer...AFTER FWD vehicles became to prevalent in the marketplace.

So...

I would first abandon, totally, the highly INEFFICIENT blower for the front condensor in favor of 2 NEW radiator fans (<$50)to FORCE airflow downward through the engine lid condensor anytime the compressor clutch is engaged.

Taking it a bit further I would run the rear lid blowers in series, 6 volts each, with the A/C enabled, and only in parallel, 12 volts each, with the compressor actually operating.

[rdoine]

How would you mount the 2 new radiator fans to force airflow downward? Wouldn't that mean they would have to be between the grill and the condenser? Or, do you mean to mount them below the condenser and pull the air through?

Anyway, sounds like a pretty neat idea.

[CharlieB]

I replaced the regular front condensor blower motor with one from the fresh air blower assembly. Basically the same size motor with lots more cfm and pretty easy to adapt. Before the mod you could barely feel any air flow if you put your hand underneath the condensor. Now I have good enough air flow that you can feel it!!

[wwest]

Originally Posted by rdoine

How would you mount the 2 new radiator fans to force airflow downward? Wouldn't that mean they would have to be between the grill and the condenser? Or, do you mean to mount them below the condenser and pull the air through?

Anyway, sounds like a pretty neat idea.

Rear spoiler = PUSH.

Otherwise = PULL.