1995 XJ6, the heater will not work. Is there a door which will switch the air from cold to hot? A blend door?

The hot/cold switch on the centre dash vent does not appear to have any effect at all on the temperature.

Help please, my sons and I are starting to get cold driving to the store!

Does the temp gauge show that the coolant is reaching "N" ? If not, the thermostat is probably stuck open and you won't get heat. Common problem.

Is the electric coolant pump working? If not, hot coolant won't circulate thru the heater core.

Those are the two most common faults.

The thumb knob in the center dashboard vent is just a trim adjustment to make the upper vent output slightly cooler or warmer than the lower vent output.

Cheers
DD

If you put your hand on the electric coolant pump (beneath the brake booster) and don't feel any vibration, then it's not working. The likely culprit are worn brushes on the electric motor. If you're uncomfortable opening up the pump to replace those brushes, then you can replace the pump. The actual Jaguar pump is insanely expensive (approx $400). There is nothing special about the pump. It's just a basic 12v 200gph impeller pump. I just replaced mine with this more durable marine pump for $35 and it works like a charm. The wiring is a simple 2 wire positive negative setup, so it's as simple as just connecting those wires to the pump.

All great answers and ill ad to them. If the pump work verify the heater valve is opening and not stuck closed, unhook the coolant hoses to the heater core and blow through the core to unclog, theyre very susceptable to clogging up and ive fixed 2 non functioning heaters already this fall this way for nothing more than labor

Excellent, thank you very much.

I'm going to tackle the thermostat first. The temperature gauge is not getting to N at all. Funny I had not noticed this until Doug mentioned it.

My experience has been that the V8 t-mostats stick CLOSED and the AJ6/16 ones stick OPEN when they fail.

Nobody seems to care when the XJ40/X300 t-mostats are open all summer but they sure come around the repair shops when winter comes.
bob gauff

Jack, never mind how I know, but be careful not to break an ear off of your thermostat housing. Two types, one uses an o-ring and one uses a gasket.

Thanks to everyone, the problem is resolved!

It was indeed the stuck open thermostat. Fixed it last night in just under 10 minutes with the help of my 16yo.

Thank you again!

What temperature rating t-stat did you buy? I just noticed my coolant temperature gauge is staying in the cold region on a 55 F degree day. I may have a stuck open t-stat.

Sorry for the delay.

I believe it to be a 189.

For those with an inoperable auxilary heat pump (the one under the brake booster), here are pics of the brushes & disassembly instructions.

1. Unscrew the 2 screws on the motor side and remove the motor body exposing the armature.
A solid magnet is glued to the interior of the body.

It'll be full of black dust. Clean the magnet and sit the body aside.



2. Inspect the brushes. They are located inside the 2 gold boxes and connected by a soldered wire.

Don't be surprised if one is missing all together. You'll notice in the above pic that the right brush is there, but the left one is missing, with just the tension spring remaining.

Lift the tabs on the end of the boxes to remove the tension spring.


3. Remove the 3 screws on the impeller end of the pump and remove the impeller (where the hoses connect to). You'll notice a 7mm nut on the end of the armature. Remove that nut, washer, and the disk they'd secured. This allows the articulation necessary to angle the armature so the brushes can be removed from their retaining boxes.

That's it. Simply reverse for reassembly. I found it easiest to place the new brushes inside their boxes, then insert the tension spring, then bend the tab over the end of the spring. Then solder the wires to the brushes.

This is a simple fix that anyone is capable of, so don't hesitate to diassemble the motor and replace those brushes. If there is not a local hobby shop to source new brushes, then take a trip down to your local thrift shop and pick up a power drill, screwdriver, or other like sized item with an electric motor. Those size motors have the size brushes you need. Simply disassemble them and remove their motors & open up the "can". The brushes will be attached to the power leads. If the brushes are slightly too large, you can easily file em down so they'll fit inside the retaining boxes on your pump.

Excellent write up Suede and great pics to go with it. Thanks for taking the trouble to post!

Could this be made into a sticky?

I was thinking that while you were typing it!

Great post, Suede!

Another helpful post with an excellent description and pics of replacing the heater pump brushes. I found almost exact replacements in a "Big semi" cab blower fan.
Before you remove the pump, it's as well to make sure that there's not some other supply problem. Best way is to unlatch the connector at the back of the heater valve, and hook up 12v to the pump to see if it runs.
The pink lead is ground and the yellow hot.You can find a handy hot under the rubber cap aft of the LHS front fuse box.

A company in California ( Eurton Electric ) that has many brushes including the one for the electric water pump for the cabin heat

The brush number for the water pump is

.15" x .15" x .35" BRUSH # 33A

3.8 mm X 3.8 mm X 8.9 mm

in their catalog

https://store.eurtonelectric.com/bru...tage33e-2.aspx