Help me Beat All this Heat
#1
Help me Beat All this Heat
Hello all, after quite a bit of searching I found some threads addressing similar problems but missing some key info. Hopefully I can turn to y'all for some advice.
First off a little info on the cat. It's an 85 XJ6. Ok, on to the issue(s).
It's had excellent heat from the time I bought it. I've rotated the knob and listened for the "whirring" sound as I've read from multiple posts. It does not exhibit any sounds at all, and acts like it is not sending signal. However all fanspeeds work including vents that will change to defrost.
I've taken the kick panel off and cleaned the contacts of all the connectors, Nothing changed. Replaced the vacuum line running from the heater valve to the fender (which btw does not feel like it has vacuum.) Does the metal source on the fender supply constant vacuum or is it sent signal to initiate vacuum from the temp knob.
What I'm thinking it is and this is solely based off searching posts... is the amplifier has gone kaput. I've found multiple posts of cold AC air only and no heat, but none of heat only. I'm assuming it's similar? Also, while I was in the kick panel I noticed two electrical connectors and a harness not plugged into anything and no other obvious open connectors. I'm thinking this could be part of the problem. Thank you.
First off a little info on the cat. It's an 85 XJ6. Ok, on to the issue(s).
It's had excellent heat from the time I bought it. I've rotated the knob and listened for the "whirring" sound as I've read from multiple posts. It does not exhibit any sounds at all, and acts like it is not sending signal. However all fanspeeds work including vents that will change to defrost.
I've taken the kick panel off and cleaned the contacts of all the connectors, Nothing changed. Replaced the vacuum line running from the heater valve to the fender (which btw does not feel like it has vacuum.) Does the metal source on the fender supply constant vacuum or is it sent signal to initiate vacuum from the temp knob.
What I'm thinking it is and this is solely based off searching posts... is the amplifier has gone kaput. I've found multiple posts of cold AC air only and no heat, but none of heat only. I'm assuming it's similar? Also, while I was in the kick panel I noticed two electrical connectors and a harness not plugged into anything and no other obvious open connectors. I'm thinking this could be part of the problem. Thank you.
#2
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
The unused connectors are common; probably not related.
First check all 4 system fuses. One is shown in your picture...the amplifier fuse in the white holder. Two more are in the RH fuse panel below the glove box. One more, another inline type, is clipped to the heater case behind the console RH cheek panel. At least one or two of the fuses must be good since your blowers work....but I can't remember which fuses do what, off hand. "checking fuses' on these cars doesn't mean just checking if they're blown. it also means making sure the end caps are corrosion-free and the clippy things are snug
Cheers
DD
First check all 4 system fuses. One is shown in your picture...the amplifier fuse in the white holder. Two more are in the RH fuse panel below the glove box. One more, another inline type, is clipped to the heater case behind the console RH cheek panel. At least one or two of the fuses must be good since your blowers work....but I can't remember which fuses do what, off hand. "checking fuses' on these cars doesn't mean just checking if they're blown. it also means making sure the end caps are corrosion-free and the clippy things are snug
Cheers
DD
The following users liked this post:
studentper (02-28-2017)
#3
The following users liked this post:
Doug (02-28-2017)
#5
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
If you still have any of 'em left the original fuses have paper tags showing the amp rating, and the fuse box cover will show the ratings as well
Anyhow....
#16 fuse 50 amp
#6 fuse 35 amp
Amp fuse 3 amp
Fuse on RH heater case 10 amp
But....wait. there's more.
Those are the British fuse ratings. Here's the USA the conversion:
British >>>>> USA
50 amp 30 amp
35 >>> 25
30 >>> 20
25 >>> 15
20 >>> 10
10 >>> 7.5
5 >>> 3
One is constant rating, the others is ....something else. I can't remember the details at the moment
And thanks for the compliment!
Cheers
DD
Anyhow....
#16 fuse 50 amp
#6 fuse 35 amp
Amp fuse 3 amp
Fuse on RH heater case 10 amp
But....wait. there's more.
Those are the British fuse ratings. Here's the USA the conversion:
British >>>>> USA
50 amp 30 amp
35 >>> 25
30 >>> 20
25 >>> 15
20 >>> 10
10 >>> 7.5
5 >>> 3
One is constant rating, the others is ....something else. I can't remember the details at the moment
And thanks for the compliment!
Cheers
DD
Last edited by Doug; 02-28-2017 at 10:08 PM.
#6
#7
Update... checked fuses and all looked good. I cleaned the terminals and fuses themselves with contact cleaner.
Question for y'all. Would a faulty "stuck" heater valve cause a constant heat issue? Mine looks original and also looks to not be functioning. I had someone adjust the temp control knob and nothing happened. Again, though I question the system's vacuum. There is none at the fender and none when I pull the line from the valve. So, I'm not sure if that's attributing to the issue or not?
Thanks for your help on this.
Question for y'all. Would a faulty "stuck" heater valve cause a constant heat issue? Mine looks original and also looks to not be functioning. I had someone adjust the temp control knob and nothing happened. Again, though I question the system's vacuum. There is none at the fender and none when I pull the line from the valve. So, I'm not sure if that's attributing to the issue or not?
Thanks for your help on this.
Trending Topics
#8
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
OK, good. When you turn the temp control knob are you hearing the 'whir'?
Question for y'all. Would a faulty "stuck" heater valve cause a constant heat issue?
But there may be more to the story
Mine looks original and also looks to not be functioning. I had someone adjust the temp control knob and nothing happened. Again, though I question the system's vacuum. There is none at the fender and none when I pull the line from the valve. So, I'm not sure if that's attributing to the issue or not?
The heater valve is prone to sticking or breaking. Sometimes they can be coaxed back into operation by manually exercising the actuator arm. Sometimes not.
However.....
The system is designed to refrigerate all incoming air first and then heat it as needed. Thus it is normal for the valve to be open in all modes of operation except when maximum cooling is asked for. When max cooling is called up on the dial vacuum is applied to the valve to close it. At all other times the vacuum is released and the valve opens.
This application/release of vacuum is via vacuum switches that are controlled by the servo. It's the servo that makes the whir noise.
Besides the vacuum hose to the heater valve you have a vacuum supply hose, located in the same neck o' the woods, identified by a white/black check valve. This *should* have vacuum when the engine is running and even a bit leftover after the engine is turned off....thanks to a reservoir tucked into the fender near the brake booster (on a LHD car). If you don't have this supply vacuum you'll need to find out why. Broken hose, most likely.
If you don't hear the whir you'll need to fix that as well !
Cheers
DD
#9
No "whir" noise that I can make out. Is it pretty noticeable? That might be why the valve never moves. It's not receiving the all cool signal. What's the best way to manually exercising the actuator arm without breaking or damaging it? I've tried a little bit. Just didn't want to mess it up.
#10
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
Is subtle....but should be no problem when you're intentionally listening for it
Right.
Just use your fingers. Moderate finger pressure will move the actuator arm unless it has seized. Try some aerosol penetrating oil in hopes it can get into the right places...but knowing that the actual valve innards might be stuck fast or physically broken
Cheers
DD
That might be why the valve never moves. It's not receiving the all cool signal.
Right.
What's the best way to manually exercising the actuator arm without breaking or damaging it? I've tried a little bit. Just didn't want to mess it up.
Just use your fingers. Moderate finger pressure will move the actuator arm unless it has seized. Try some aerosol penetrating oil in hopes it can get into the right places...but knowing that the actual valve innards might be stuck fast or physically broken
Cheers
DD
#11
I'm pretty positive the temp control knob isn't doing anything or "whiring". I've listened for it deliberately. It also doesn't seem like the AC Amplifier is "talking" to the other parts of the system. Not sure if those two are connected?
I know portions of it work (Compressor clicks when I turn the blowers on low and all the way through Defrost. So at the very least that is working (baby steps) ha.
Back to the whiring (or not) in my case. What part needs to be checked and replaced? Is it fairly easy to access it? Thank you again for your help Doug
I know portions of it work (Compressor clicks when I turn the blowers on low and all the way through Defrost. So at the very least that is working (baby steps) ha.
Back to the whiring (or not) in my case. What part needs to be checked and replaced? Is it fairly easy to access it? Thank you again for your help Doug
#12
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
Yes, they're connected.
The amplifier is the brain of the system. It takes in the signals from the temp control knob and the temp sensors and decides what to do. It commands the servo. The servo is the workhorse of the system...operating all the flaps, vacuum valves, and blower speed switches. It's a little motor that operates a gear driven camshaft....thus the whir
I know portions of it work (Compressor clicks when I turn the blowers on low and all the way through Defrost. So at the very least that is working (baby steps) ha.
Good !
Back to the whiring (or not) in my case. What part needs to be checked and replaced? Is it fairly easy to access it? Thank you again for your help Doug
However the servo can be unplugged and tested to verify that it does indeed work. If you wanna do that, post back.
Oh....one other very easy check.......
With the console LH 'cheek panel' removed you can see the heater core pipes. One of the pipes has a small switch attached. it has two wires. Jump the two wires together and see if anything changes.
Cheers
DD
#13
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
Better yet, let's use the info we just learned from ICS !
Don't disconnect the wires at the switch. Jaguar gave us test leads which can be jumped together, as seen in your pictures, to accomplish the same thing. They're the brown and brown/yellow wires with the vacant grey connectors.
Cheers
DD
#14
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,742
Received 10,755 Likes
on
7,101 Posts
I never noticed or realized this before, despite that fact that the diagrams clearly show the existence of these test wires. [hand hitting forehead]
There's always something new to learn, isn't there?
Cheers and thanks
DD
#15
Yes sir, and for you to learn it on these cars still says A-lot! Ha Well, I tried jumping the two leads. Nothing changed. Still no "whiring" which I thought was odd since I'm basically bypassing the amplifier right?
Also not having any luck freeing up the valve. I've let penetrating oil sit overnight. It feel like it's seized up. I just can't get any movement out of it.
Also not having any luck freeing up the valve. I've let penetrating oil sit overnight. It feel like it's seized up. I just can't get any movement out of it.