1983 Jaguar XJ6- AC Blowers not turning on when switch is turned on dash

Jochen is dead on: if you have a deadline, make sure that it will run on that day. Fix the important parts first, that is, read up on how to jack the car up. Best by the rear and front suspension, they are rubber mounted and heavy. Good shove before crawling under, don’t risk your life.
Change the brake fluid, make sure it stops, new tyres. Look for structural rust.
Make sure the engine runs and give everything a good clean. Eliminate rattles, new oil, go through the transmission.
With the time left you can have a look at the blowers, but I am sure you will find the cure. I‘m 23 also and my XJ is just a year younger, but not well documented at all and with its own problems, many of them fixed by now.

I‘m sure your grandfather in law will be very happy even if the fans are not in order yet, should you not come around to them by then.
Texas, even then, prioritize. Is the AC still on charge, how long did it sit? :slightly_smiling_face:

David

Nikolas,
I was thinking about your two inoperative heater blower motors today and wondering what I would to if this was my car. I would want to easily and positively identify whether each of the heater blower motors worked or not. When I was sorting out a blower motor issue in my 1984 XJ6 Vanden Plas I removed the lower right cheek panel in the passenger foot well, pulled the wiring harnesses from behind the carpeting, located the connector where the Green-Slate (grey) and Black wires going to the both heater blower motors were, separated the connectors, and then applied an independent 12V DC power source to test each of the heater blower motors one at at time see if they worked. The connector is shown in the attached picture circled in yellow and my red and black leads for the 12V DC are also visible. If you do this be sure to disconnect the battery in the car and use another 12 VDC source for the + and - to power the heater blower motors. In my case it was good news that both blower motors worked, but further trouble shooting lead me to problems elsewhere. As a result of this test I knew that both of the heater blower motors worked which was a good thing because removing and replacing a heater blower motor is not for the faint of heart. :wink:

Paul

Thanks for all the advice. And I’m deffiently trying to stay on track as far as getting the functional aspects of the car running first. Deadline is mid july next year so quite a but of time.

History of the car:
It sat 8-10 years not started and sealed in a garage. 1-2 years before it was sealed away it received a large mechanical over haul. New hoses everywhere, engine tuning, gasket replacements, and just touch up work to make it hum again, the transmission was not touched because it has been and is still currently pristine! It also had new suspension i believe put on as well. Main issues that caused the car to be sealed away were in the electrical system. He was getting old and to busy to keep tracking down this or that nuisance fuse and relay, so it began to live in the garage. So even after 10 years of sitting i really started with a leg up on resto! Fluids and filters got changed right before the first time i fired the engine.

The one major fix that’s on my agenda, but i am just waiting for a bit to do due to time Nd money requirements are new fuel tanks and and a new fuel change over solenoid. The tanks are ok for the most part but i would like to get them refinished to stop any kind of rust or corrosion that may try to weasel its way in them when the car is back in use more. The fuel change over soleniod in my car is just gone. I have done all the tests to know that its completely gone.

Before my current problem with non starting the engine was purring great. I believe the distributer was replaced/upgraded in the last 10 years with the other engine touch ups. So hopefully that’s still in tact and functional. But we will see. And ill deffiently be holding onto any parts (like the original coil) for this car long after i get the issues solved. My hope is that once the car was operational i can look into servicing those parts I order to have backups.

So long story short aside from the fuel tank job i really only had these more trivial tasks ( ac, the radio antenna, ect) left to fix before. It got down daily maintenance items like brake pads or body/paint work which is something i plan to send it off for, as i lack the equipment and experience to do that job correctly. So ya that’s kind of where I sit for the most part 85% of my issues have been failed relays with this car. I have been rather blessed thus farm with how issues seem to be resolving them selves in the various system

Nikolas,
Fighting Texas Aggie Class of 2019

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A quick-check would be to verify power on the brown/white at the relay, Paul - then connect it to the relay’s yellow (low-speed) wire. And/or the red (intermediate high) - or feed those wires 12V directly…

If the fans run it’s fair to assume they work - and if not…oh…well…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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Frank,
I considered testing the heater blower motors at the Relay as you suggested but decided against it because that would not have achieved my goal of testing each blower motor separately. Testing at the relay as you suggested would have tested both heater blower motors together.
Through my experience in completely parting out three Series III XJ6s I knew where the harness with the Green-Slate/Black wires to both heater blower motors was located, and shortly after removing the right cheek panel I was able to test each blower motor separately. This was positive confirmation that each of my heater blower motors were good and allowed me to look elsewhere for my issues.

Paul

So Changed the relay. now every blower works except the center dash blower and the passenger dash blower!!! They sounded like they have junk in them so a cleaning is probably due. Thanks for the help everyone!!

I think the centre vent only opens on full cooling? Mine‘s always open, but not supposed to. It creaks and is unhinged on one side.
Is the passenger dash blower just closed? Can you move the adjuster on the bottom? I don’t think there is any way of closing just this one. If you mean the defroster, try moving the flap by hand (the grille pegs will break off…) and it is possible that its actuator is done.
Happy it is mostly working now!
David

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The two blowers works together, Nikolas - into a plenum. There is no specific ‘center dash blower’ or ‘passenger dash blower’…

The air flow is controlled by flaps and vents; the fans blows all air through the AC evaporator - the flaps channel more or less air though the heater core, for heating, or bypasses the heater core, for cooling. Then other flaps directs the air ‘upwards’,for the center vents or defrosters, and or ‘downwards’ to the cabin, front and rear.

The positioning of the flaps and vents are operated by the AC servo, using mechanical pushrods and vacuum actuators, electrically operated by microswitches. The servo is controlled by the AC amplifier programmed to set the flaps for acquiring and maintaining the temp set by the temp controller. An in-car temp sensor monitors cabin temp, and the AC amp compare the two to position the flaps and vents as appropriate…

In full cooling, the heater core is bypassed and the center vents are open (by vacuum). In full heating, the air passes through the heater core, the center vents are closed (default position) and the air led into the cabin. The defrost vent are closed (by vacuum) in all switch position - except ‘def’. The side screen vents are manually operated by a thumbwheel - open; they blow at fan speeds, with temp according to servo setting.

So your problems are likely not junk in the fan plenums - it is likely the servo being in a position that is intended for heating. Turning the temp control to ‘65’ should open the center vents - unless cabin temp is below 65F.

A faulty AC amp, loss of vacuum or various other faults will cause malfunctions - to complicated to explain at this stage…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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There is always a slight bleed to the windshield.
It could be the vacuum switch on the servo (I did not verify it is there) on the side of the unit if the center doesn’t open after a minute in 65°. Maybe leave that for later now that the fans run… you’re mostly there.
The passenger vent should be coupled to the drivers‘ I think.

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Indeed, David - a slight bleed at the defrost at all times to keep the windscreen clear…

Frank
xj6 85 Sov Europe (UK/NZ)
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Nikolas,
I have had rodents build nests in the heater blower motors of my XJ6 parts cars that sat in my barn for years awaiting disassembly. Once I removed the blower motors of the nesting materials, nuts, and various pieces of debris, they worked fine.
I also had a case of an inoperative center vent that wouldn’t open as it should with the A/C on in my 1984 XJ6 Vanden Plas. That problem was due to a failed solenoid vacuum valve (RTC670) that controls the center vent flap. Once I removed and replaced the RTC670 the center vent returned to working properly again when the A/C was on and the cabin temperature was above the temperature set on the temperature knob.

Paul