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Discussion Starter #1
On our way to a car show near Duluth yesterday, my newely charged A/C system was not blowing cold at all even though the fan was working in all 4 speeds, But Then the fan quit working as well.
I checked fuses and all were good. Fuse in line near relay on top of the A/C suitcase was good. All other elec. things work fine, just the fan and now the A/C compressor are both dead. Where should I start to look for this problem?
If I cant find it quick, the Camaro stays home on our trip to Denver Wed. morning.
:confused:
 

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Fan control switch in the dash. Mine just did the same thing today and I've got power thru the fuse up to the switch. Worked fine Friday, now today nothing. Now I have to pull either the radio or the instrument panel to get access to the switch. Maybe I'll luck out and it will only be a loose connection.
 

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the thick orange wire, around the suitcase has a connector, Always found that the contacts in this connector burnt out,
 

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Discussion Starter #4
Rob are you talking about the line with the fuse in it that I have? It leads from the fuse box to the relay on top of the suitcase with a 25Amp fuse in line there on my car.
I redid that whole group of wires last week, new plug and new crimped brass contacts, melted the wire wrap around all the connections etc.
I will be going over that whole area for sure and check the thermal overload thingy in the side of the suitcase too.
grrrrrr :confused:

 

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Discussion Starter #5
Man this gets frustrating. I pulled the whole switch assembly from the dash and replaced the switch, I had a donor on the shelf, luckily. Still nothing works.
I have power on the 12guage brown wire to the assembly, but none from there to the switch at all. I also have 12V down the orange (red lead in my pic where I made a new patch) to the relay on the suitcase. But no power from the relay purple or orange. I then pulled the wire from the fan motor and ran jumper wires from the battery to the fan motor directly and it did not work at all either but I do have continuity across the motor poles .
Im getting crossed eyed again, any suggestions?
1. should the motor work with direct 12v to it?
2. Should the relay 'pull in' with fan switch on and sliders in A/C position?
3. Should I have power at the fan switch all the time? If so on which color wire? I have none there now.
4. Where should I aim the shotgun ?

:eek:

Thanks for some ideas to go from now?
 

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Power for everything in the A/C system, except the high speed feed to the fan comes through the fan switch. The fan switch is fed from the 25 Amp heater fuse in the fuse panel through a #14 brown wire. There is a Lo Blow switch on the left upper corner of the heater control panel that is controlled by the left heater slider. That is inline with the fan switch.

The contacts on this switch are closed in either vent, A/C and heat, and open in off which is way at the top of the slide. I've had trouble with the contacts on this switch before. It is very sensitive to the lever being in the right position, and the contacts will pit.

If you put the slider into A/C and the temperature control in COLD and don't have battery voltage on the tan wire terminal on the low temperature switch on the side of the A/C suitcase in the engine compartment, your problem is probably in this switch.

The other wire off of this LO Blow Switch is a #16 Tan wire that goes to the fan control switch. This line should also have have voltage in every position except OFF.

Slide the Vent/AC lever up and down a few times with the key on then move the fan switch through its various speeds and see if the fan or the fan relay clicks on and off. I just got mine to work by doing that. Don't know how long it will last, but it looks like the low blow switch on mine is on it's way out.

As far as the fan running when you put 12Volts directly to it, it should run as long as your ground wire is intact. The fan ground ties into the same ground wire that the relay uses and it attaches to the firewall with a big sheetmetal screw above the valve cover.

The fan should run in all speeds, at all time except when the left control is slid all the way to the top of the control.
 

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Nice job on the repair click. Those old connections get cruddy over the years. Oxides build up and while they still conduct electricity they also create resistance. And when you pull current through a resistance, it dissipates power has heat. Thus the melted terminals. Trouble is, usually when you repair one, the next weakest link in the chain goes.
The new connection reduces the circuit resistance and allows more current to flow, frying the next oxidized connection in the chain. That's when most people sell their cars and why we love em. :rolleyes:

Once you find out where the next grimlin lives, consider doping your connections with dialectric grease. Some manufacturers use white lithium, which works, but dries out over time and exposure to heat. I bought some dialectric grease at a local hardware store in a tube. It looks like plain ol' brown axle grease. I dope everything with it that stands a chance of exposure to moisture or carries high current.

-dnult
 

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Discussion Starter #8
Thanks again Mark, I will print this, add it to your other trouble shooting ideas and try to find the culprit.
I have full continuity on all wires from the control assembly to the relay and plug that goes into the resistor area.
I ran 12v from battery direct to motor connections I had pulled off, the terminals are clean and yet the motor wont work at all. I also cant get the relay to 'click' or pull in with the slide control. Now I will check that area again per your ideas.
I will report back on it when I make headway.
Wonder how hard it is to get blower motors? :confused:
 

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Just remember A/C motors and the fan cage are different than non A/C motors and fans. The A/C fan is a bit deeperr then the non A/C ones. A non A/C motor would probably work OK for a while, after you figured out a way to put a ground terminal on it that is.
 

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Blower Motor is $16.99 in stock at Autozone and most other auto part sotres. Just bought one a week ago for my 69 fact AC car
The fan did seem to see too close to the motor for my comfort so I applied a little jb weld to the bottom of the shaft to stop the fan a little sooner on the shaft, works perfectly!
 

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Discussion Starter #11
WOOOHOOO Got it figured out!
Thanks Mark and dnult and others. I had a cup of coffee and stood next to my car staring at the assembly manual again this morning. Thinking, why does compressor and fan all go out at once? Mark mentioned the low blow switch which I had not played with yet and sure enuf, that white slide button was all the way pushed in and I had to pull it back with pliers. The contacts were also not working on my Ohm meter when I pulled and pushed it. I swapped out the one I had on a donor assembly, (glad I bought that on ebay for $27). Plugged all the wires back in and presto, I have compressor engagement, throttle solenoid, and fan but only the 3 speeds. That low blow switch must have thrown a current and blew out the relay for high speed.
I followed the wiring diagram and the low blow sends power via the tan wire to the low temp plug on the suitcase which makes the green wire connection back to the compressor. When my low blow switch died, the tan was not completing that connection so it all died at once.
Ive ordered a new high speed relay and a new low blow switch cuz I dont know how reliable my donor switch is either. The low blow switches are no longer made and not available from normal catalogs anymore either but I was referred to http://www.obschevy.com/ who had a few of them genuine GM in the box for only $28. When I get back from Denver, the parts will be here and I can re-assemble it all again.
In the photo, the old switch had roller pins of brass that had worn thru the seperator plastic piece and they were mated together and shorting out on both sets of points at the same time. I tried to clean them up and re-install but the plastic seperator is broken or worn off completely and they pins just roll back together again. Thought maybe somebody would like to see what that switch looks like inside.
Thanks again guys. I think I have become a half-a**ed expert on this problem now. Take a cold one out of petty cash on me.





[ 07-08-2003, 11:13 AM: Message edited by: click ]
 
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