Fuse for AC Fan

My fan will not blow hard when on high. I've heard there is a fuse that controls this but I've been unable to locate it. Any ideas where it is on a '79? Also, where is the orfice?

Bill

If you locate the high speed blower relay, the red wire is the constant power feed. On the 79 it may come through a fusiable link, not a fuse. Look around the right valve cover area and see if you spot a wiring harness with the red wire, and a few more, in a harness connector. This connector often burns and loses the power to the blower relay, then no high speed.

The orifice is in the high pressure line from the condenser to the evaporator. You will see a connector, and on one side of the connector, about 4 inches away, you will see a small crimp in the line. The orifice is located inside the line between the connector and the crimp. The high pressure line is smaller than the low pressure line.

Ken... Thanks for your help. You where right on. The power lead was good so I replaced the relay and presto -high speed fan. Now that the high speed fan works I’ve uncovered another problems (isn’t that always the case). Now the fan never shuts off, always running on low speed no matter where the controls a set. Also air only comes from the floor vents. I’m assuming I need to get behind the controls and see what’s up with all the vacuum lines and control cables. Thanks again for your help.

If you have Astro Vent system, the fan does not shut off with the key on. Low is as low as you get. If it does shut off with the key off, you have Astro Vent. Can't fix what ain't broke.

I just read everything in this thread but it looks like I missed something about replacing the relay. My fan no longer works on high and medium and I can't hear or feel it on low but the ac still works. I assume the main fuse is good. Also, I checked my wires around the relay under the hood and saw no problems. Thus, I assume the problem is the relay. I can hear something clicking when I move the fan switch but nothing happens. Make sense it is the relay?

Anyway should I just replace the relay and hope for the best. I hate to replace parts that may be ok (this can get expensive and is definately a waste of time) but it looks like my best shot.

Any thoughts or recommendations?

Herb ('80 coupe)

I just read everything in this thread but it looks like I missed something about replacing the relay. My fan no longer works on high and medium and I can't hear or feel it on low but the ac still works. I assume the main fuse is good. Also, I checked my wires around the relay under the hood and saw no problems. Thus, I assume the problem is the relay. I can hear something clicking when I move the fan switch but nothing happens. Make sense it is the relay?

Anyway should I just replace the relay and hope for the best. I hate to replace parts that may be ok (this can get expensive and is definately a waste of time) but it looks like my best shot.

Any thoughts or recommendations?

Herb ('80 coupe)

kstyer said: If you have Astro Vent system, the fan does not shut off with the key on. Low is as low as you get. If it does shut off with the key off, you have Astro Vent. Can't fix what ain't broke.

yeah with astrovent a heater hose bypass OR shutoff almost becomes essential..

If you hear the relay click, the power to the switch is okay. The purple wire that comes from the relay powers the fan. See if there is any power there. If so, check the ground on the fan motor. If not check the red wire to the relay, and the remaining heavy wire to the relay for power. If both inputs are good, but there is nothing on the purple output, the relay is bad.

Once you locate the relay it is really easy to check. You can use one of those 2" 12V batteries and connect one lead to each side of the coil side on the relay. You should use a meter on the contact side and you should see the contact close when voltage is applied and open when you remove the voltage. If not, bad relay. If the relay checks good, you could try cleaning all contacts of the relay with emery cloth to see if that helps.

FLA VETTE said: If the relay checks good, you could try cleaning all contacts of the relay with emery cloth to see if that helps.

or a pencil eraser cleans good too..