69 AC Help needed - Team Camaro Tech
Heating & Cooling Heating, cooling and air conditioning

 
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post #1 of 14 (permalink) Old Jun 6th, 17, 04:10 PM Thread Starter
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Ed
 
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69 AC Help needed

Thought it might be best to start a new thread to explain my AC issue vs tag onto an old thread.

I just finished rebuilding my original AC. Good news is it blows cold so I'm pretty happy.

The problem is as follows:

Regardless of where the left (temp) lever is or regardless of where the center lever (diverter) when I turn on the fan, the AC clutch engages. It should not turn on when on VENT.

I've read all the threads I can find and am not sure if this is an issue with the diverter or the lo blo switch.

I've looked at the wiring diagram and it looks like it could be either. My gut says it's the lo blo. I haven't pulled things apart yet to start experimenting but wanted to see if anyone knows before I do.

Any help is greatly appreciated.

Ed
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post #2 of 14 (permalink) Old Jun 8th, 17, 10:32 AM Thread Starter
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Re: 69 AC Help needed

I needed to get to the diverter switch to see what's going on. To do this, I took off the bottom vent and then the glove box.

I was able to see the diverter switch which had two things wrong. First, the wire that was supposed to plug into the two prongs was only plugged into one and second, the "plunger" on the switch was getting stuck when pushed in. I took off the switch and sprayed it with WD40 which helped but it was still not quite right. I will order a new one given the PITA to get it out.

From what I can tell, the only thing this should fix is the fact that the compressor remains on when the middle lever is on heat. I still won't fix my compressor going on when the VENT is on. I believe that's an issue with the 3 prong switch attached to the heater control. I'll tackle that next and believe the radio needs to come out to get to it.

What I find very interesting and perplexing is if you search eBay for the diverter switch (3955900) they all call it the lo blo switch and the switch on the heater control (3929093) is called the heater blower switch. Am I missing something? I believe the 3929093 which they call the heater blower switch is the lo blo switch.

Ed
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post #3 of 14 (permalink) Old Jun 8th, 17, 11:15 AM Thread Starter
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Re: 69 AC Help needed

After staring at the wiring diagram, I can not figure out how the compressor was turning on at all because only one of the wires was attached to the diverter switch. From what I can tell power gets to the compressor through this switch unless it's pushed in when the center level is on heat . So if only one of the sides of the two prongs was connected, how would the compressor ever turn on??!!

I must be missing something.

Ed

Last edited by emdoller; Jun 8th, 17 at 11:30 AM.
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post #4 of 14 (permalink) Old Jun 8th, 17, 02:46 PM
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Re: 69 AC Help needed

Anybody have some ideas for Ed's issue here?


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post #5 of 14 (permalink) Old Jun 8th, 17, 02:58 PM Thread Starter
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Re: 69 AC Help needed

Thanks Brian. This one is perplexing. I just ordered new switches for both the diverter and the heater control. I haven't had a chance to pull the radio to check the heater control switch but ordered one anyway. Just the fact that the Compressor was turning on when on VENT makes me believe that switch has issues as well.

As I wrote, I can't figure out how the compressor was turning on when only one side of the diverter wire was plugged into the switch (the other side was hanging off and unconnected). May just need to wait and see what happens when I get the radio out and the new switches installed to see what it does vs trying to figure out why it was doing what it was doing although I am curious!!

Ed
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post #6 of 14 (permalink) Old Jun 10th, 17, 12:03 PM Thread Starter
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Re: 69 AC Help needed

I mapped out the entire electrical system and understand it. Amazing combination of electrical, mechanical, and vacuum to manage this heating and cooling system.

So here's where I am:

My diverter switch wasn't hooked up right and gets stuck when it's pushed in. I have an NOS one on order.

I was just about to take out my radio to test my lo blo switch on the heater controls when I decided to hook up a DVM to the light green (LG) wire that goes to the diverter. If that switch is working correctly , I should get 12v to that switch via the LG wire coming from the lo-blo switch if the left control is on anything except OFF and VENT and that's exactly what I got. This is in turn passed to the compressor. This means the lo-blo switch is working and I don't need to take the radio out. Too bad I purchased an NOS lo-blo switch and an NOS fan switch just in case.

So I'm hoping that all I need to do is replace the switch on the diverter.

Lastly, I also realized that there is a fail safe provision if you turn the AC on with the fan on OFF for the diverter switch to send power through the FAN switch to run the blower motor on low.

Anyone having problems, let me know as I think I can help debug.

Ed
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post #7 of 14 (permalink) Old Jun 10th, 17, 12:48 PM Thread Starter
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Re: 69 AC Help needed

Well I decided to run one more test as I await the arrival of my diverter switch. I hooked up a DVM to the tan wire that connects to the diverter switch and goes to the fan switch and the thermal switch that connects to the compressor. From what I can tell the tan wire does two things:

1) with AC on it delivers power to the thermal switch and ultimately to the compressor
2) applies voltage to the fan switch such that it turns the fan on low only if the fan switch is off (this is the fail safe)

What I found was this wire was actually delivered voltage when I moved the fan switch from OFF position. This would explain why the compressor was kicking on when the left lever was on OFF or VENT. Do that explanation is closed.

What I don't know is why this is occurring. The only logical reason I can come up with is the fan blower switch isn't working properly. Looks like I need to pull the radio after all. Luckily I ordered one of these.

Any other suggestions?

Ed
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post #8 of 14 (permalink) Old Jun 10th, 17, 02:38 PM Thread Starter
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Re: 69 AC Help needed

Update: I shorted the diverter switch and fan works like it should when in OFF position. It turns on low. I then looked at the wiring diagram trying to figure out how power could be getting to the tan wire (compressor power) when I had no connection at the diverter. As far as I could tell there are only three potential sources:

1) from the power applied to the switch itself (terminal #1)
2) it was feeding back into the switch from the relay via orange wire and shorting to the tan wire terminal 6
3) feeding back via the resister bank and shorting to the tan wire (terminal #6)

I hooked up my DVM to the tan wire in the engine bay and turned on the fan

Got ~10 V on the tan which is my problem as the tan wire at the diverter switch was disconnected. I then pulled the orange and purple wires on the relay and that did nothing. I next pulled the plug in the resistor and the voltage went to zero. I then went wire by wire using continuity to see which wire was shorted to terminal 6 of the fan switch. It turns out it was terminal 3 (light green wire) which is physically right next to terminal 6. Looks like I need to remove the radio after all. It appears either the switch is bad or someone purposely shorted those out. I can't imagine it being anything else.

Would love to hear if others believe this to be true.

Ed
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post #9 of 14 (permalink) Old Jun 10th, 17, 02:41 PM Thread Starter
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Re: 69 AC Help needed

Update: I shorted the diverter switch and fan works like it should when in OFF position. It turns on low. I then looked at the wiring diagram trying to figure out how power could be getting to the tan wire (compressor power) when I had no connection at the diverter. As far as I could tell there are only three potential sources:

1) from the power applied to the switch itself (terminal #1)
2) it was feeding back into the switch from the relay via orange wire and shorting to the tan wire terminal 6
3) feeding back via the resister bank and shorting to the tan wire (terminal #6)

I hooked up my DVM to the tan wire in the engine bay and turned on the fan

Got ~10 V on the tan which is my problem as the tan wire at the diverter switch was disconnected. I then pulled the orange and purple wires on the relay and that did nothing. I next pulled the plug in the resistor and the voltage went to zero. I then went wire by wire using continuity to see which wire was shorted to terminal 6 of the fan switch. It turns out it was terminal 3 (light green wire) which is physically right next to terminal 6. Looks like I need to remove the radio after all. It appears either the switch is bad or someone purposely shorted those out. I can't imagine it being anything else.

Would love to hear if others believe this to be true.

Ed
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post #10 of 14 (permalink) Old Jun 11th, 17, 04:29 AM
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Re: 69 AC Help needed

Ed, you are really deep into this! I applaud your tenacity! I wish I could help, but never got this deep into AC. Luck and keep digging!

Kevin


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post #11 of 14 (permalink) Old Jun 11th, 17, 05:02 AM
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Re: 69 AC Help needed

Ed,
It is rather unfortunate that you haven't received adequate support with this issue. I feel like due to the fact 99%, or at least the majority of this forum either does not have A/C, or they update to a modern system (ie Vintage Air), the few knowledgeable resources that could lend you support have not logged on recently or are not notified when there is a question related to their area of expertise. It will be someone here that will know someone and contact them directly to log on and help. In the mean time, I did locate a forum that specializes in original, classic A/C systems HERE, including specific year models. It's called the "AutoACForum". I understand that TC is the quintessential place for answers and resources for Camaro, but it is also a place where team members help out any way they can, and since I don't know anything about original Camaro A/C systems, this is the only way I know to help you. The bottom line is getting you fixed, and if you have to go somewhere else for now, I am okay with that.

One question I have; Is your system updated for 134A or are you still using R12?

I hope I don't get flamed for presenting you with a resource outside of this forum, but I wanted to contribute because I am a member of this forum.....

Brett....

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post #12 of 14 (permalink) Old Jun 11th, 17, 10:12 AM Thread Starter
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Re: 69 AC Help needed

Brett,

Really appreciate the response. I figured the reason this thread is light on replies is because many don't have the original AC. It's a blessing and a curse.

I will figure this out and hope to be the expert once I do. It's a great opportunity to learn how this works and the reason I love these old Chevrolets! I can tell you my 67 Vette was much easier to work on when it comes to AC.

It's an original system and I just had the compressor rebuilt, I flushed all the oil in the system because someone had "converted" it to 134 and did a half a** job and didn't flush the original oil. New hoses, O rings, and POA, R12 and it's working well despite me having a vacumm issue I need to fix to turn the heat off.

I'll check out the other forum and keep this thread updated shoukd someone else have a similar issue.

Once I get the fan switch and the diverter switch that should (I hope) solve the compressor always turning on issue.

Stay tuned!!

Edl
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post #13 of 14 (permalink) Old Jun 13th, 17, 10:48 AM Thread Starter
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Re: 69 AC Help needed

Update:

I pulled out the radio, center console, and the seat so I could try to see what was going on with the fan switch. I couldn't see anything but decided to try and pull off the connections and test them before taking off the dash pad and replacing the fan switch.

Luckily I could reach up and was able to pull them off. After getting them off I went to the engine compartment and checked to see if there was continuity between the LG wire and the tan wire (this was my issue) prior to pulling off the connections and there was. So this meant it wasn't the switch!!

I then looked up and down the wires looking for the short. I did see that there was black tape around the LG wire and a Gray wire but didn't think twice because I was looking for a short between the LG wire and a Tan wire. I stepped back and looked at the wiring diagram and and went back to the two fan switch connectors. LG, yes, OR, yes, Y, yes, LBL, yes, Tan... NO!! but there was gray wire! And guess what, the gray wire was the one taped to the LG wire. I pulled the tape off an they had been tied together and might I add quite professionally!

So two things: 1) the wiring diagram C60 E9 is wrong! The wire going from tab 6 of the blower switch is Gray, not Tan... or at least mine is. 2) my guess is this "fix" (toeing the two together) was done because the diverter switch was not working and they would rather have AC on at all costs.

I fixed the wires and everything is now working as far as I can tell. I'm still waiting for my new diverter switch to finish up. was worried that I wouldn't be able to get the fan switch connectors back on but it wasn't too bad.

Time to go put the car back together minus the glove compartment until the diverter switch arrives.

Ed

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post #14 of 14 (permalink) Old Sep 7th, 17, 07:58 AM
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Re: 69 AC Help needed

I have been reading your thread.
I have exactly the same problem with my Camaro. Mine is a 1969 SS 350 with factory AC.
When I bought the car, all of the under the hood components for the AC had been removed except for the dog house on the firewall. I replaced all parts and got it charged. All worked good except when I pushed the left lever down to the "vent" position (which is the first notch), the AC compressor kicked in, just like yours. It shouldn't kick in until the lever is push down to the "Max Air" positon. I had already replaced the plunger style heater & AC control blower switch. Because the compressor kicks on immediately, I don't have any ventilation system. It's either no vent of any kind or AC.
I started to wonder if the switch was a "two stage" switch. If pushed part way it would turn on the ventilation and if pushed all the way it would turn on the AC.
Have you had any luck figuring yours out?
I too, have had little to no luck finding someone who has knowledge of this system with the AC option.
I also had to install a throttle kick up solenoid to kick the RPMs up a little when the AC is on. Otherwise it pulled the engine down so much that it almost kills.


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