Hi all,

In addition to the transmission issue that I posted, I am having yet more issues with the car. The heat!!

I had gone through the entire heating/air conditioning system when I first acquired the car. I pulled the entire unit out of the car, learned the functions of the system, refurbished the case, painted it, replaced the foams, lubricated the linkages, replaced the gunked up and leaking heater core, the whole nine yards.

The air conditioning didn't work again as I never charged the system, but I never drove the car in the summer time (avid motorcycle rider). Since putting the car back on the road on this past Friday the heat actually worked just fine while driving the car Friday night to work. In fact, it was working too well, heating the cabin substantially. Much more than I wanted. I adjusted the temperature dial (on the left) and then nothing! Not to say that the fans stopped working, but that the heat stopped flowing. I removed the right lower vent kick panel where you can see the servo working and it does not. With the car running I can cycle through the functions: the fans speed up and slow down as selected, but the servo does not move. Any thoughts on what went wrong? A fuse? The amplifier? The Ranco? Vacuum controller? Anything...

I always appreciate positive feedback.

 

I know I read a post a while back on the servo, but I don't remember the title. You might find it by searching different key words in the search bar.

 

1) check the little black/white check valve hanging on the side of the battery between two vacuum lines, one of which goes thru the firewall to the Servo, this valve gets clogged and causes symptoms.

2) confirm the Heater Valve is opening and closing: engine running, place the Mode switch in NORMAL, then watch the linkage below the valve while a second person moves the TEMP control from 65 to 85. The linkage should move, opening and closing the heater valve. This is to confirm the valve is receiving vacuum.

 

Thanks Jose,

I forgot to mention that I did away with the original (crappy) heater valve in lieu of a modern (more positive close) water valve. So no moving parts to see. I think that I could feel the heater core pipes to see if they get hot.

I suspect it's something as simple as a fuse, but I had to throw it our there to see if there's something that I am overlooking. I mean, to have it be working at one moment (just days ago) to not working on the same trip... More head scratching.

 

Jose is on the right trail. if the matrix gets no hot water, there will be no heat.


The generic valves come in two modes. default on, or default on!! I forgot which Jaguar needs.


And, under the battery, nicely hidden are two spigots for vacuum hoses. these are used by the Dellanair to function. off or reversed???? But, one is smaller than the other. I visited there recently in my car. Got them on correctly, touch alone.


And, I got mine to warm the cabin nicely after getting the car's engine nice and warm and then excercising both knobs, temp and fan speed.


In the past, mine has gotten fussy. I just went into defrost mode and got the warm air I wanted....imperfect, yeah, but warm...


Carl.

 

Hi all,

Just wanted to share an update on my "No Heat":

I never actually fixed the problem, but through fidgeting around with all the wires that feed the servo and such I managed to get the unit working again. I simply unplugged the multi-connector on the passenger side of the unit, plugged it back together and it works again! Now it works "flawlessly", adjusting the heat automatically as it should. But every now and then, usually while I'm in traffic or simply driving, the unit will go into full defrost mode, by itself, indicating that the servo has stopped working and it defaults to the basic setting (blowing cold air). I then have to disconnect that connector again to allow the system to reset itself, re-connect it and everything works well again.... very odd, but beggars for heat can't be choosey!!

 

Tom:


Yeah, one of the Jaguar vagaries??? Disconnect and connect scrubs off microscopic corrosion that interrupts current flow!!


Same with switches and other electric controls. Excercising them often restores them to service???


And, at times, just revving up the engine and getting more VOLTS flowing works???


Prince Lucas is mysterious, no question about it...


Carl

 

being an intermittent symptom, I still think the problem is the little check valve hanging by a vacuum hose next to the battery, a hose which is also connected to the Servo.

remove the valve first noting the direction of the arrow on it, and then submerge it in a pan of warm water to dislodge any grime inside it; Then blow into it from both sides to see if if it fixes it.

 

Rather than starting a new thread, figured I'd add to this one. Same basic issue, no heat. Brief history on my situation, '86 VdP, sat for around 6 months for various reasons. Before sitting, the heat worked as normal, the water heater valve did leak when the arm moved. After getting back on the road, no heat. I assumed the water valve had rusted shut so I got one of the plastic universal ones, mentioned in a different thread, from my local parts store. Installed, still no heat. Looking through this thread, I pulled the black and white check valve, cleaned and verified it worked as it should. I also disconnected the vacuum line to the water valve assuming that would tell me if I installed it backwards. I then took the side panels off in the cabin and checked fuses, and unplugged and replugged connectors. Still no heat. Any other ideas?

Thanks,

Eric

 

One other clue, if I switch the temp adjustment slider under the radio all the way over to the heat side, I do feel like I am getting heat out of the center vents, but not the side vents, still cool there.

Eric

 

Get down and under or however. Can't see them, only feel them.
Two spigots on the fire wall. Engine bay to cabin. Vacum lines.
Loose or reversed ands no heat!!!


I've found that the red-blue slider has little effect???


Carl

 

By design the red-blue slider offers just a slight variation on upper-versus-lower output temperatures.

Correct usage is to set the main temp control as desired, wait for the cabin temp and system to stabilize, and then use the slid control to make the face level vents slightly warmer or cooler than the footwell vents.

It's a subtle thing.

Cheers
DD

 

First things first.

Turn temp selector to max heat setting. Listen closely. Do you hear the whir of the servo motor? Does the output air divert almost entirely to the footwell vents? If so, it indicates that the system has at least 'received and understood' the request for heat.

Cheers
DD

 

the slider under the radio has no effect on the air temp, it is only a useless way to balance the cool air and hot air between the center vent and the other vents.

did you get a NORMALLY OPEN heater valve??

 

Thanks for chiming in. I will see if I can find the hoses you mention Carl.

I will check the servo activation as you suggested Doug.

Jose, here is a link to the heater valve I installed:

http://www.autozone.com/cooling-heating-and-climate-control/heater-control-valve/everco-heater-control-valve/792952_0_0/?checkfit=true

Oh, regarding my comments on the slider thing, didn't mean insinuate I was getting maximum heat out of the center vents, just felt warmer than the cold air coming out of the side vents.

Thanks again,

Eric

 

Tom or Eric, I am familiar with that heater valve, I installed one in my 65 S type, but these heater valves come in two operating modes: Normally Open - closes with vacuum -, and Normally Closed - opens with vacuum -. The Series 2 and 3 XJ use a Normally OPEN heater valve, the Series 1 XJ and older Jaguar use a Normally CLOSED heater valve. The link you referred me to does not say. I would confirm that you got the correct mode heater valve. I buy them at Car Quest, who have the same heater valves in the two modes.

 

I remember blowing through the pathway for the coolant and it was open, so I assume it is open with no vacuum, but I'll see if I can double check.

Eric

 

OK. Checked to see if servo sounds were happening and here is what I found. Turning the temp knob around, including to max heat, resulted in no sounds or change in air flow coming out of the footwell vents. The car was up to operating temperature. I tried the fan speed settings on low, auto and high, no change. When I switched the speed setting knob to defrost, I did hear flaps moving and more air coming out of the windscreen vents. All air was still cold. Btw, my A/C is currently not working, need a new compressor. Outside temps are in the 50s.

What do I check to get the knob working again?

Thanks,

Eric

 

Begin with the easy stuff. Check all four climate control fuses. Two in the RH fuse panel, one inline fuse clipped to the right side of the heater case behind the console RH 'cheek panel', and one more inline fuse on the amplifier ground wire behind the console LH cheek panel

That's because 'defrost' bypasses the automatic functions...the brain of the system (the amplifier) is out of the picture in defrost mode

That the flaps moved at least proves the servo is fundamentally operational. That's good.

Cheers
DD

 

Alright. Checked everything out with my multimeter. Everything tested out OK. Still no heat unfortunately.

I manually moved what I assume to be one of the flap arms that I could see on the LH side. I thought the spring pulled it back into place, but now there is no air coming out of the center vents. Either way I still have only cool air.

Another piece of the puzzle, I replaced the amplifier a few years back, as my a/c would fluctuate from cold to heat at the time, so it is a relatively new part.

Thanks,

Eric