What is this piece on the firewall?

[polarnj]

Looks like it has 2 looped vac lines and some kind of cable coming out of the left side, I think it goes into the lower firewall

I looked up a whole bunch of 69 Polaras and Fury's on the web and didn't see this on any of them

 

[413]

Time delay relay for the factory A/C system.

A mysterious device, It's in the manual.

 

[polarnj]

Anyone have pics of one that's properly connected? Or is mine the way it's supposed to be?

 

[Sixpactogo]

It appears to be the way is should be. Those time delays are supposed to run the AC for a short time to aid in de-fogging the windshield. I suspect by now most no longer work or are needed as these cars are seldom daily drivers. I would ignore it.

 

[polarnj]

It appears to be the way is should be. Those time delays are supposed to run the AC for a short time to aid in de-fogging the windshield. I suspect by now most no longer work or are needed as these cars are seldom daily drivers. I would ignore it.

If it's not working the ac will still be ok?

 

[Davea Lux]

If it's not working the ac will still be ok?

A/C will still work.

Dave

 

[Sixpactogo]

If it's not working the ac will still be ok?

Yes. As I said, it only affects running the AC when the heat and defrost is selected. That is it's only purpose.

 

[Trace 300 Hurst]

When I rebuilt my system I put a ball bearing in the vac line to the time delay so that whatever was going on in that mysterious device, it wouldn't happen anymore AND I wouldn't be dealing with a vac leak. I put it all together nice-nice so it looked proper. As discussed above, when the car was a daily driver on a miserable cold rainy day, the device "might" have kept the windshield from fogging, but we know the rear window defogger/blower thingy didn't really work either!

As a Sunday driver collector car, it's just not necessary to work properly.

 

[Sixpactogo]

When I finished the resurrection of my 68 Charger, I verified the time delay worked. That was back in 2016. I'm pretty sure I have not used the defroster at all since then. I have used the AC every year though.

 

[Big_John]

As discussed above, when the car was a daily driver on a miserable cold rainy day, the device "might" have kept the windshield from fogging

I can't remember where I read this. One purpose was that the compressor was guaranteed some running time in the off season.

It was always stressed that the AC needed to be run once in a while to keep everything "happy" and working well, so this made a lot of sense to me.

 

[Sixpactogo]

I can't remember where I read this. One purpose was that the compressor was guaranteed some running time in the off season.

It was always stressed that the AC needed to be run once in a while to keep everything "happy" and working well, so this made a lot of sense to me.

Yeah, it makes sense to me also. For me, the trouble is Wisconsin weather pretty much puts my cars in hibernation for 5 months and I'm not willing to move to a warmer climate.

 

[polarnj]

When I rebuilt my system I put a ball bearing in the vac line to the time delay so that whatever was going on in that mysterious device, it wouldn't happen anymore AND I wouldn't be dealing with a vac leak. I put it all together nice-nice so it looked proper. As discussed above, when the car was a daily driver on a miserable cold rainy day, the device "might" have kept the windshield from fogging, but we know the rear window defogger/blower thingy didn't really work either!

As a Sunday driver collector car, it's just not necessary to work properly.

View attachment 703253

Good idea to plug the vac line, I'm assuming it's the one coming out of the left side?

I'm wondering where the vac source for this device is

 

[polarnj]

Yeah, it makes sense to me also. For me, the trouble is Wisconsin weather pretty much puts my cars in hibernation for 5 months and I'm not willing to move to a warmer climate.

Same here in NJ, salt all over the roads right now

 

[polarnj]

When I finished the resurrection of my 68 Charger, I verified the time delay worked. That was back in 2016. I'm pretty sure I have not used the defroster at all since then. I have used the AC every year though.

How do you check if it's working?

 

[Sixpactogo]

It has been a few years so I'm not positive but I think I turned on the heat and defroster and checked the compressor to see if it was running for a short time then shut off. Pretty sure I got the info from the FSM. I have not tested it since 2015 so the procedure could be different.

By the way. you asked where the source of vacuum was. It is the small hose off of the intake tee feeding the heater box. You can't just plug that off or you will lose your heater controls. If you want to disable the timer just unhook the brown & blue wires on the timer. Leave the vacuum hose alone.

 

[polarnj]

It has been a few years so I'm not positive but I think I turned on the heat and defroster and checked the compressor to see if it was running for a short time then shut off. Pretty sure I got the info from the FSM. I have not tested it since 2015 so the procedure could be different.

By the way. you asked where the source of vacuum was. It is the small hose off of the intake tee feeding the heater box. You can't just plug that off or you will lose your heater controls. If you want to disable the timer just unhook the brown & blue wires on the timer. Leave the vacuum hose alone.

uh-oh, I don't have any kind of tee coming from the intake. Must be why my heater is stuck coming out of the vents. The only vac line is going from the intake to a round vac tank in front, which then goes into the firewall. Any pics of what it's supposed to look like?

 

[Sixpactogo]

uh-oh, I don't have any kind of tee coming from the intake. Must be why my heater is stuck coming out of the vents. The only vac line is going from the intake to a round vac tank in front, which then goes into the firewall. Any pics of what it's supposed to look like?

So........Manual brakes with AC. That is a strange combination for a C body. Apparently you have vacuum headlight doors also since you have the vacuum cannister up front. Hopefully the Factory Service Manual will show you the routing. Maybe someone with a similar car will join in with some info.

 

[Big_John]

Apparently you have vacuum headlight doors also since you have the vacuum cannister up front.

No vacuum headlight doors. It would be an electrical motor if it had them.

The vacuum canister is for the HVAC system.

 

[polarnj]

So........Manual brakes with AC. That is a strange combination for a C body. Apparently you have vacuum headlight doors also since you have the vacuum cannister up front. Hopefully the Factory Service Manual will show you the routing. Maybe someone with a similar car will join in with some info.

I have power brakes not manual, didn't know that round thing at the front pass side (lower left corner) is for nonexistent headlight doors ?

 

[Sixpactogo]

OK......You have power brakes. I see a hose on your brake booster. It is coming off of the intake Tee. Apparently, as Big John mentioned, the canister at the front is for your AC system. The hose going back thru the firewall is the vacuum for your heater / AC controls. You mentioned your heater controls are stuck blowing out of the vents. More than likely you problem is in the controller behind your heater push buttons. Pretty common failure. You will need to remove it and either replace it or have it rebuilt.