I have a unusual issue with the blower, The unit works, blows hot/ cold temp setting works as far as I can tell. But it all is running like its low on power or is stuck on a low setting the air blows but barely enough to heat the car on a cold day or cool on a warm day. Nothing like when it worked properly the ac would freeze you out of the car. But basically the low setting (don't make me laugh) isn't there, auto blows like low originally, and high is barely above the low speed setting. I haven't done a lot of work on the blower or ac system and am looking for opinions or ideas as what to consider as a likely suspect with the malfunction.

 

Not sure if your car has a pollen / cabin filter or not?
If so, it may be time to change this.


If the AC isn't getting as cold as it should be, or once was my guess would be a low refrigerant issue, perhaps needing topping up?


Other than that it will be more costly for sure, just a thought and worth looking into

 

Been out reading the book, and researching on the web. The levels are good I think its mainly due to the fact its really hot outside right now. The blower the fan rpm sounds the same almost on all the settings it barely changes. I'll take a look on the pollen filter and see if it has one. Worst case I can always go pull parts from another car and replace my stuff, I do have access to a good parts car thankfully. But its really odd the fan rpm is weak, turn it to heat and it almost turns off the blower. so I am wondering if it might be the Temperature sensor for the climate control system

 

In my very limited experience, i would bd checking the blower relay (has 4 relays in side it, one for each fan speed) if one of the relays is blown, it automatically goes to the next one. Yours may have blown the 2 higher fan speeds. I could be completely wrong. If you look in the thread titled 'a/c dazed and confused' you should find some wonderful advise and diagrams.
TO quote many people here, Doug will know. ☺

 

what year XJ-6 ??

if you add this info to your signature, we don't have to ask.

There are no pollen filters in the Series 3 XJ-6 (1980-1987).

 

I didn't think so, but never say never with a English car I have learned very well with my old Land Rover. I thought I had put the year but noticed after you said that I had not. I have a 1984 xj6 , same car in the old Equalizer show.

 

ok, same year as mine. 1984 was a very good year for the XJ-6.

if the blowers are not reaching 4th speed, it must be an electrical issue.

Check the following very carefully:

get on your back in the passenger side front floor with a bright lamp or flashlight and an old toothbrush or a small paintbrush;

on the innermost side of the kick panel, towards the firewall, you will see what looks like a small circuit board, with a little diode / resistor.

look to see if it is covered with grime and grease or dirt. Clean it with the dry brush, front and back. This is a Incoming Air Temp Sensor.

Obviously the blowers are working so that is a good sign;

Next check would be the large black (or brown) Relay behind the driver's side "knee" panel behind the handbrake; Remove the two black plastic Vent screws and pull the panel towards the front of the car. You will see the relay with a bunch of wires connected to it.

Look at the center wire that has a phillips screw and make sure the screw is tight. Best to disconnect the battery before doing this because if you touch another contact with the screwdriver as you tighten the screw, you will blow a fuse.

If no change whatsoever, you will need to substitute the large relay to see if the problem is the relay itself.

 

So spent the last 3o minutes crawling in the floorboards. The screw on the wire was tight as could be. I looked at the sensor or what looked like the sensor and everything else near it. Was pretty clean. Gave everything a good dusting with some compressed air anyways. IT is doing something different but not much now there is a difference between low and the auto setting, Low is really low, like the slightest amount of airflow. auto kicks up a little and blows some. there is no high setting same as auto and defrost is the same as the high and auto setting. I'm really thinking it might be the relay at this point. Read somewhere that if part of the relay fails you only get low or which ever setting is left working or something like that. I'm going to try and find a donor car to test the relay option and hopefully that solves it. Summer is fast approaching and that car in Fort Worth summer temps, is not fun.

 

yeahh, the large relay is really 4 small relays inside the case, 1 relay per blower speed.

if you open it you'll see, they are interconnected by thin wires which in my opinion can easily fry, leaving one or more relays incomunicado from the others.

I'm not saying that IS the problem, but it usually can be.

The other problem can be the actual Mode switch, but best to troubleshoot by substituting the large relay first.

 

Maybe the motors need new brushes. They are 31 years old and untouched since they were installed. Cars with climate control use the blowers a lot more than manually controlled heater units.

 

Could be, and I am so not against getting or rebuilding the motors for it. Going to hit up a friend who has several parts cars and grab relay and test it before pulling everything. With some luck it will be back to freezing us out of the car soon.

 

those motors had to be very reliable for the simple reason the blower case is so difficult to remove and re-install.

In my car I removed both blower cases (following the factory Service Manual) and noticed there was a lot of grime in the case and in the motors, and also the system of linkages inside the case are kept in place by plastic pins which deteriorate and break.

also there are foam seals for the two case Flaps which desintegrate and then the flaps make metal to metal noises.

it's a maintenance issue, doing those blower cases takes patience, it is a very involved system of twin blowers, twin cases and quadruple flaps. Do not attempt it without the factory manual, which you can download here free.