Ok here is where I am with my heater issues....

Replaced and relocated the heater valve and it is working properly.
Replaced the thermostat with a 190 deg model and my Jag finally gets up to operating temp.
Both fans are working and change speeds at low and high settings

Outside temps have been anywhere from the teens to 41 today over the last few weeks.


With the temp on 75 and the fan on high I get a nice warm air from the vents on the center console and the rear vent. The upper vents are cool to cold. The bottom vents on the blower cage are both closed and she's pulling air in from the cowl vent like crazy.

Any thoughts?

 

*Correction - As long as there is power to the solenoid there will be vacuum to the blue hose and the blower vents will remain in the "Fresh Air" mode.

With the engine at operating temp and the heat off the vents remain in the "recirculation" mode with the bottom flaps open. When the heat is turned on they close and the system is in "Fresh Air" mode pulling air in from the cowl vent. My understanding is that at Max Heat or Max Cool the system would go into "recirculation" mode. With temps in the low 20s at times I'd expect it to be in Max Heat mode. I'm wondering if I have a bad temp sensor.

My next thought is to wire an ingnition powered switch to the solenoid to give me control of the air source.

Any thoughts?

 

Any idea what voltage this solenoid needs?

Any other thoughts?

 

My bet is on the A/C Amp....

Sometimes I send several hours testing these things, and it's amazing the difference you get from one to the other.
One amp will give all A/C... Some are stuck on heat only.... Some change the air coming from the vents (locations), and then occassionly one will do it all correctly...

If you want to test what I'm talking about... I have a couple that are stuck on heat only, that I've been debating on whether to throw out or not.
I'll be glad to send you one, free of charge, just to see if it has an effect on the way your system operates....

David Boger
www.EverydayXJ.com

 

It sounds as though the system and amplifier may be working OK. That is if you can regulate the temp between hot and cold. Usually if the amplifier fails you'll be stuck on full hot or full cold. I think you may need to run the flap and linkage adjustments to get the temp right high and low. Attached is a document I put together several years ago with the procedure and tool numbers etc.

The recirc door operation you describe seems to be correct as well. They only open to the interior for max heating and cooling, most of the time they are closed.

Good luck.

 

Great info, Steve.

Cheers
DD

 

Thanks for the info. Looking through the notes, one thing that stands out is that the dash vents really don't change temp when you move the temp differential thumbwheel.

 

It's a very subtle change at best.

Cheers
DD

 

In my case it's still hot at the rear vent and side vents and cold at the dash vents in either position.

 

I understand. What I'm saying is that the thumbwheel adjustment isn't likely your problem....as it's only capable of changing the bias by a few degrees.

I'd go with the flap adjustment procedure as outlined above.

Cheers
DD

 

If I'm not mistakin', I believe the thumbwheel [trim temp] would only alter the temp plus or minus four degrees, and only the face vent temp at that. I'll have to find all my old Delanair stuff and check.

Cheers,