Ok it’s hot as $...! Help with cool?
#1
Ok it’s hot as $...! Help with cool?
clearly the ac isn’t working on my 88’ xjs. But not only that I can’t even get it to blow air temp in. I replaced the heater valve the other day. It was stuck open but the new unit made no difference. I’m wondering if the whole vacuum system in my car is junk. Twisting any temp knobs or the the cold/warm lever does nothing. Should it make any noise when moving the dials or switches. Like motors moving flaps etc? Cause I have zero sounds etc. just about 120 degrees of air. So naturally I keep the fan at zero and the windows down... even then the heat of the engine alone warms the cabin. I want to switch the ac to 134 but at this point I don’t know if anything besides the blower fan is working! Best place to start? Test the compressor? Test flaps? Sorry for the scatterbrained questions
#2
Best place to start is checking the 4 system fuses: #10 and #11 in the main (LH) fuse box, #5 in the aux (RH) fuse box, and the inline fuse which, as I recall, is near the RH side of the main a/c case, behind the RH console 'cheek panel'.
The servo motors are very quiet so you might not hear them over the fans. Might be easier to hear/see operation of you remove both cheek panels.
Cheers
DD
The servo motors are very quiet so you might not hear them over the fans. Might be easier to hear/see operation of you remove both cheek panels.
Cheers
DD
#3
clearly the ac isn’t working on my 88’ xjs. But not only that I can’t even get it to blow air temp in. I replaced the heater valve the other day. It was stuck open but the new unit made no difference. I’m wondering if the whole vacuum system in my car is junk. Twisting any temp knobs or the the cold/warm lever does nothing. Should it make any noise when moving the dials or switches. Like motors moving flaps etc? Cause I have zero sounds etc. just about 120 degrees of air. So naturally I keep the fan at zero and the windows down... even then the heat of the engine alone warms the cabin. I want to switch the ac to 134 but at this point I don’t know if anything besides the blower fan is working! Best place to start? Test the compressor? Test flaps? Sorry for the scatterbrained questions
#4
Best place to start is checking the 4 system fuses: #10 and #11 in the main (LH) fuse box, #5 in the aux (RH) fuse box, and the inline fuse which, as I recall, is near the RH side of the main a/c case, behind the RH console 'cheek panel'.
The servo motors are very quiet so you might not hear them over the fans. Might be easier to hear/see operation of you remove both cheek panels.
Cheers
DD
The servo motors are very quiet so you might not hear them over the fans. Might be easier to hear/see operation of you remove both cheek panels.
Cheers
DD
l would start testing at the vacuum system. Start at manifold and just check each line in turn. If you don't have vacuum you will not have a/c flap control and heater valve will be stuck open. The a/c vacuum solonoids are easy enough to get to in order to check them and their vac lines.
Side question... everything seems in order and still no cold ac. would it be better to just switch the system over to 134 or try and give it a can of R12 first?
#6
i really have no idea. I don’t hear any clicking from it. I’m new to the xjs climate control too... is it always on? There’s no ac button? Or does pulling the temp knob out turn it on? Little embarrassing but I don’t have the owners manual so it’s a little confusing.
#7
OK, just a minute. Before you can start fixing it, we need to define what the problem is.
Question 1 : Do you get air flow when you set the fan speed switch not to zero?
The way it's supposed to work is that the A/C compressor is always on, IF the fan speed is not set to zero. This might seem wasteful because the A/C compressor is on even on a cold morning when you have full heat. That's the way it is.
Question 2 : on the temp knob, can you pull it out? If so, you have Delaniar Mk III. If the temp knob has no feature where it pulls out, you have Delaniar Mk II.
On the Delanair Mk III, pulling out the temp knob overrides cabin temp control using feedback from the cabin temp sensor, and just sets the air temp.
So try this : Fan on medium, pull out left hand knob. With the engine warm, vary the set temp. The air temp and direction should vary.
My understanding is that when you have the fans running, AND you vary the temperature, there is no response - to either the direction of air flow, or to the temperature. Is that correct? If so, forget about vacuum for now, as the servo motor is electric.
Question 1 : Do you get air flow when you set the fan speed switch not to zero?
The way it's supposed to work is that the A/C compressor is always on, IF the fan speed is not set to zero. This might seem wasteful because the A/C compressor is on even on a cold morning when you have full heat. That's the way it is.
Question 2 : on the temp knob, can you pull it out? If so, you have Delaniar Mk III. If the temp knob has no feature where it pulls out, you have Delaniar Mk II.
On the Delanair Mk III, pulling out the temp knob overrides cabin temp control using feedback from the cabin temp sensor, and just sets the air temp.
So try this : Fan on medium, pull out left hand knob. With the engine warm, vary the set temp. The air temp and direction should vary.
My understanding is that when you have the fans running, AND you vary the temperature, there is no response - to either the direction of air flow, or to the temperature. Is that correct? If so, forget about vacuum for now, as the servo motor is electric.
Last edited by Mark SF; 07-15-2018 at 05:03 PM.
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#8
The compressor operates in all modes: heating, cooling, blending, defrost. Thus, no separate A/C button
In your case I'd say the compressor is not engaging as the engagement click is quite distinct....and you're not hearing it. Confirmation would be visual: the pulley is always turned by the drive belt, obviously, but when the clutch engages you'll see the outer section of the pulley spinning as well.
Pulling the temp knob out gives manual hotter-colder temp control. Pushing the knob in reverts to automatic temperature control.
Cheers
DD
#9
Just read the bit about the fans only working on high speed. Major clue this. This means that the climate control is being inhibited for some reason. As far as I know, there are 3 possible reasons for this :
1) The heater core is not getting hot. Bizzarely, the entire climate control system is inhibited when the heater core is not hot, including A/C, except that an override is allowed for high fan speed to give some defrost. There's a thermo switch on the hot water line.
2) No power to the climate control amplifier.
3) Blown climate control amplifier.
You're wasting your time messing with vacuum, and the A/C compressor. You need to get the other fan speeds working, then proceed.
1) The heater core is not getting hot. Bizzarely, the entire climate control system is inhibited when the heater core is not hot, including A/C, except that an override is allowed for high fan speed to give some defrost. There's a thermo switch on the hot water line.
2) No power to the climate control amplifier.
3) Blown climate control amplifier.
You're wasting your time messing with vacuum, and the A/C compressor. You need to get the other fan speeds working, then proceed.
#10
Just read the bit about the fans only working on high speed. Major clue this. This means that the climate control is being inhibited for some reason. As far as I know, there are 3 possible reasons for this :
1) The heater core is not getting hot. Bizzarely, the entire climate control system is inhibited when the heater core is not hot, including A/C,
1) The heater core is not getting hot. Bizzarely, the entire climate control system is inhibited when the heater core is not hot, including A/C,
This feature is designed to prevent getting blasted with cold air when the system is in heating mode. when the coolant get warm enough to actually provide cabin heat the switch lets the system turn out.
As a test the switch is easily bypassed. Some leave it bypassed, in fact. Just join the two wires together
You're wasting your time messing with vacuum, and the A/C compressor. You need to get the other fan speeds working, then proceed.
Cheers
DD
#12
OK, just a minute. Before you can start fixing it, we need to define what the problem is.
Question 1 : Do you get air flow when you set the fan speed switch not to zero?
The way it's supposed to work is that the A/C compressor is always on, IF the fan speed is not set to zero. This might seem wasteful because the A/C compressor is on even on a cold morning when you have full heat. That's the way it is.
Question 2 : on the temp knob, can you pull it out? If so, you have Delaniar Mk III. If the temp knob has no feature where it pulls out, you have Delaniar Mk II.
On the Delanair Mk III, pulling out the temp knob overrides cabin temp control using feedback from the cabin temp sensor, and just sets the air temp.
So try this : Fan on medium, pull out left hand knob. With the engine warm, vary the set temp. The air temp and direction should vary.
My understanding is that when you have the fans running, AND you vary the temperature, there is no response - to either the direction of air flow, or to the temperature. Is that correct? If so, forget about vacuum for now, as the servo motor is electric.
Question 1 : Do you get air flow when you set the fan speed switch not to zero?
The way it's supposed to work is that the A/C compressor is always on, IF the fan speed is not set to zero. This might seem wasteful because the A/C compressor is on even on a cold morning when you have full heat. That's the way it is.
Question 2 : on the temp knob, can you pull it out? If so, you have Delaniar Mk III. If the temp knob has no feature where it pulls out, you have Delaniar Mk II.
On the Delanair Mk III, pulling out the temp knob overrides cabin temp control using feedback from the cabin temp sensor, and just sets the air temp.
So try this : Fan on medium, pull out left hand knob. With the engine warm, vary the set temp. The air temp and direction should vary.
My understanding is that when you have the fans running, AND you vary the temperature, there is no response - to either the direction of air flow, or to the temperature. Is that correct? If so, forget about vacuum for now, as the servo motor is electric.
The climate control system is 'on' unless the mode control knob is turned to 'off'.
The compressor operates in all modes: heating, cooling, blending, defrost. Thus, no separate A/C button
In your case I'd say the compressor is not engaging as the engagement click is quite distinct....and you're not hearing it. Confirmation would be visual: the pulley is always turned by the drive belt, obviously, but when the clutch engages you'll see the outer section of the pulley spinning as well.
Pulling the temp knob out gives manual hotter-colder temp control. Pushing the knob in reverts to automatic temperature control.
Cheers
DD
The compressor operates in all modes: heating, cooling, blending, defrost. Thus, no separate A/C button
In your case I'd say the compressor is not engaging as the engagement click is quite distinct....and you're not hearing it. Confirmation would be visual: the pulley is always turned by the drive belt, obviously, but when the clutch engages you'll see the outer section of the pulley spinning as well.
Pulling the temp knob out gives manual hotter-colder temp control. Pushing the knob in reverts to automatic temperature control.
Cheers
DD
#13
The default mode for the heater valve is open, so heat is always the fallback. It takes vacuum to close it That being said, it's worth a check of the right side intake manifold to see if the vacuum pipe is actually connected to the maniolfd. It's a small pipe, on my 94 it's maybe 1/8" dia plastic line.
For the fans, they bypass the control system on high and get 12V directly from a relay. For the lower speeds, they are controlled steplessly by a darlington transistor on a printed circuit in the blower fan housing. Those transistors are known to fail, so that will cause the motor to not run when anything less than high is called for. If you're handy with electronics, it's not that difficult to replace the transistor and rebuild the board. I'm pretty sure the circuit diagram and step by step photos are either here or on Jag-lovers.
For the fans, they bypass the control system on high and get 12V directly from a relay. For the lower speeds, they are controlled steplessly by a darlington transistor on a printed circuit in the blower fan housing. Those transistors are known to fail, so that will cause the motor to not run when anything less than high is called for. If you're handy with electronics, it's not that difficult to replace the transistor and rebuild the board. I'm pretty sure the circuit diagram and step by step photos are either here or on Jag-lovers.
#14
The default mode for the heater valve is open, so heat is always the fallback. It takes vacuum to close it That being said, it's worth a check of the right side intake manifold to see if the vacuum pipe is actually connected to the maniolfd. It's a small pipe, on my 94 it's maybe 1/8" dia plastic line.
For the fans, they bypass the control system on high and get 12V directly from a relay. For the lower speeds, they are controlled steplessly by a darlington transistor on a printed circuit in the blower fan housing. Those transistors are known to fail, so that will cause the motor to not run when anything less than high is called for. If you're handy with electronics, it's not that difficult to replace the transistor and rebuild the board. I'm pretty sure the circuit diagram and step by step photos are either here or on Jag-lovers.
For the fans, they bypass the control system on high and get 12V directly from a relay. For the lower speeds, they are controlled steplessly by a darlington transistor on a printed circuit in the blower fan housing. Those transistors are known to fail, so that will cause the motor to not run when anything less than high is called for. If you're handy with electronics, it's not that difficult to replace the transistor and rebuild the board. I'm pretty sure the circuit diagram and step by step photos are either here or on Jag-lovers.
#15
Air conditioning blower control
I did this job and removing the blower was probably the most difficult job I've ever done on a Jag, personally. But experiences vary.
Cheers
DD
#16
Here's some info:
Air conditioning blower control
I did this job and removing the blower was probably the most difficult job I've ever done on a Jag, personally. But experiences vary.
Cheers
DD
Air conditioning blower control
I did this job and removing the blower was probably the most difficult job I've ever done on a Jag, personally. But experiences vary.
Cheers
DD
#17
Well I got to take a look today... I’m getting no compressor clutch engagement and I know it’s because it has zero R12 in it. I took off the filler port cap and touched it with a key.... I’d say there was about .25psi that escaped and then nothing. All fuses are good. Haven’t gotten to follow all the vacuum lines yet. The fan wants to turn on when I put it on low... I get the fan to kick on at high but then I can turn it down to medium or low from there. I really think I just need to fill up the Freon. Is switching to r134 a big job or easy?
#18
All that is really required is changing the fill ports and then filling it up. However, you obviously have a leak, so you need to find the leak first. A common suspect is the retaining plate on the compressor that holds the hoses on. It's really a bit thin, and bends a bit when tightened by the bolt in the middle and doesn't hold the hoses square to the compressor.
At this age, it can be many things. I just fixed the AC on an 81 XJ12 and it ended up being two tiny corrosion pinholes in the condensor that I had to braze up. That after I went through and changed the O rings in every joint, changed the compressor and the receiver dryer. It had been apart before, and whoever put it together didn't know what they were doing and put in wrong sized O rings.
To do AC right, you need all the tools: vacuum pump, full gauge set and hoses, can tap and thermometer. Also patience and thoroughness.
My leak finding procedure is I have a hydrocarbon detector good to 5 PPM, and I have made an adapter so I can use my BBQ propane bottle to connect to the gauge set. I vacuum the system, give it about 5 psi of propane and then go over each joint with the detector. It works quite well to find leaks.
At this age, it can be many things. I just fixed the AC on an 81 XJ12 and it ended up being two tiny corrosion pinholes in the condensor that I had to braze up. That after I went through and changed the O rings in every joint, changed the compressor and the receiver dryer. It had been apart before, and whoever put it together didn't know what they were doing and put in wrong sized O rings.
To do AC right, you need all the tools: vacuum pump, full gauge set and hoses, can tap and thermometer. Also patience and thoroughness.
My leak finding procedure is I have a hydrocarbon detector good to 5 PPM, and I have made an adapter so I can use my BBQ propane bottle to connect to the gauge set. I vacuum the system, give it about 5 psi of propane and then go over each joint with the detector. It works quite well to find leaks.
#19
All that is really required is changing the fill ports and then filling it up. However, you obviously have a leak, so you need to find the leak first. A common suspect is the retaining plate on the compressor that holds the hoses on. It's really a bit thin, and bends a bit when tightened by the bolt in the middle and doesn't hold the hoses square to the compressor.
At this age, it can be many things. I just fixed the AC on an 81 XJ12 and it ended up being two tiny corrosion pinholes in the condensor that I had to braze up. That after I went through and changed the O rings in every joint, changed the compressor and the receiver dryer. It had been apart before, and whoever put it together didn't know what they were doing and put in wrong sized O rings.
To do AC right, you need all the tools: vacuum pump, full gauge set and hoses, can tap and thermometer. Also patience and thoroughness.
My leak finding procedure is I have a hydrocarbon detector good to 5 PPM, and I have made an adapter so I can use my BBQ propane bottle to connect to the gauge set. I vacuum the system, give it about 5 psi of propane and then go over each joint with the detector. It works quite well to find leaks.
At this age, it can be many things. I just fixed the AC on an 81 XJ12 and it ended up being two tiny corrosion pinholes in the condensor that I had to braze up. That after I went through and changed the O rings in every joint, changed the compressor and the receiver dryer. It had been apart before, and whoever put it together didn't know what they were doing and put in wrong sized O rings.
To do AC right, you need all the tools: vacuum pump, full gauge set and hoses, can tap and thermometer. Also patience and thoroughness.
My leak finding procedure is I have a hydrocarbon detector good to 5 PPM, and I have made an adapter so I can use my BBQ propane bottle to connect to the gauge set. I vacuum the system, give it about 5 psi of propane and then go over each joint with the detector. It works quite well to find leaks.
Well today for the first time testing the hvac system everything seems to work except the ac. I’m used to most cars turning the fan on and it instantly blasting away. Today I finally just turned the fan to low and It turned on it’s just nice and quiet. Then I twisted the temp knob. At its coldest the fan is blowing pretty decent trying to cool the car(not going to happen with no Freon). So while still in low I twisted the temp knob to the highest heat. The fan auto slowed down. So the system is all working I just don’t have Freon. I’m going to switch over to 134 because I can’t rely on swap meets to carry R12 if I need a boost. I can find it pretty easy now but future?
#20