69 burb rear ac relay

[highwinger]

So I bought this 69 burb recently that has "factory air". Well I found it has rear air but not front (no vents or evap). I assume that means the AC isn't factory and the rear is an add-on albeit a factory system. Were they made with rear only?

I'm having difficulty finding any info online about the part,location and wiring. In fact very little acknowledgement of rear ac period. My Haynes book has a schematic showing the relay but doesn't distinguish between front & rear. Are they the same? Where do the two systems tie in together with sets of controls for the same compressor? I don't have front anyway, but am considering get the Old Air heater box swap for AC/De-Ice/Heat. Anyone with experience with them?

(enuf of my own thread creep) Other posts say the relay is a common problem when the hi won't work but the lo & med will. Does anyone have a pic or diagram of where I can find the relay or what to replace it with?

I've been reluctant to tear into it again since the overhead trough is brittle.

Thanks in advance,
Bill

[Bigdav160]

I don't think front and rear A/C was available until 1972. Before that it was rear A/C only in the Burbs.

Dig through this link and you might find a parts book and service information.

[highwinger]

Thanks for the links...that's AWESOME. (Too bad work doesn't like the link.) I did some more searching last night and didd see a thread stating the overhead air is all the 69 had. After I get the rear fans working on HI, I'll see if I need to add front air too.

Meanwhile, any feedback on Old Air Products v. Classic Auto Air v. Vintage would be helpful. At first glance, the first two sound like they have larger evap than Vintage. OAP touts more efficient/direct air flow vs. bends or ducting. OAP also says theirs is more servicable since it's not a glued housing. OAP heater replacement is lowest cost too ~$600 vs $800 for CAA.

[highwinger]

Originally Posted by Bigdav160

I don't think front and rear A/C was available until 1972. Before that it was rear A/C only in the Burbs.

Dig through this link and you might find a parts book and service information.

I was downloaded all the 69's expect the chassis overhaul. Will try again.

I'm surprised the service manual only showed the front A/C. I haven't seen any reference to the overhead (rear) A/C. So still no joy on the relay :-(

[highwinger]

I spent Fri evening, all day Sat and Sun morning fixing this A/C relay problem. I surely didn't expect it to take that long, but it runs on hi now. Being in FL, hi is the only useful setting.

In troubleshooting, I found the hot wire wasn't connected and I couldn't figure out where the other end was so ultimately, I had to run a new power line to the relay. The toughest part was getting it down the rear pillar. Something in there was stopping me from fishing the wire down or up. I ended up clipping the tail light cable and used it to pull through the new wire. I wasn't happy about it, but it worked.

The attached schematic closely represent the setup except I'm not sure if the part on the right is a compressor switch or some sort of temp sensor. It has a wire that runs on the output side of the evap coils which isn't shown in the schematic.

Unfortunately, I have a little condensate drip from the passenger side drain tube where it mates to the plastic plenum. I'm not sure if the plenum actually channels the water to the tube or if I disconnected the tube somehow. It doesn't pull out of the plenum. Anyone have experience with this? I'm not looking forward to opening that back up, especially since I could never really get to that area.

Like others have said, the rear AC works ok. It doesn't freeze you out by any means. There's enough heat from the firewall at highway speed to almost negate the AC. Primarily, I will use it sparingly like on the highway to reduce the wind noise and during the rain when I have to put the windows up. So, it'll do. After I get the other little things done and find a spare $800 lying around, I might go for a front aftermarket AC system.

Thanks for the help & the links.

[60sIron]

Here's a picture of the overhead for the air. In 69 it wasn't rear only. They used the plastic overhead to distribute the air rear to front. I'm sure not many survived as the plastic cracks. I spend a lot of time getting it to look good and work as new. I was glad it looked good...... Because even at top efficiency it was poor. By the time the cold air reaches the front it's not very cold. On a hot day, when you need air, the roof of a suburban is like a giant solar panel. Notice I even blocked the rear most outlets. If I keep my sub. I'm going to install a new front air and ducted it to the center seat.

[highwinger]

Did blocking the rear ports help up front much?

Do you know how the drain is connected to the evap? My drain tube is dripping between the plenum and pillar.

If I put in front air, I'm leaning towards Old Air Products: http://www.oldairproducts.com/catalo...ge-p-8165.html
but I don't have front ac already.

You definitely have it looking good

[60sIron]

I had to cut the line to take down the plenum. I used an irrigation coupler to reattach it. There is another one on the other side. So 2 drains 1 on each side. The line runs inside the rear pillar and exits underneath. Blocking the rear outlets helps somewhat. But seriously, this was good in 1969! Almost 50 year old technology......... I love old cars and trucks. If you what to be a purist and drive one every once and awhile fine. If you're like me and what to drive one and use it, up grade where you can. AC is one area that you can.

[highwinger]

I think my drip comes from that interface of the tube & plenum. Does the condensate drip right onto the plenum and run down to the tube? Or, does the tube connect directly to the evap inside?

[60sIron]

Into the plenum then into the tube.

[Bigdav160]

I would guess it's similar to my '72

[highwinger]

Thanks guys. That helps.

[highwinger]

Update...I put some sealant around where the plenum meets the drain tube which seemed to stop the drip inside.

I'm primarily using the AC when it's raining (no sun) and it works great unless I'm at speed on I95. Then, the heat from the front challenges the overhead A/C. It stays comfortable, but it's borderline. Driving around town is fine.