Checked all 3 fuse boxes. Checked all relays. I understand that these units have relays inside the air-con but having difficulty getting them out to verify. However I'm suspicious that both quit this morning. Could be one was shy and the other just gave out I guess as the air volume never did seem a lot. Possible climate control module? The manual button never did seem to do anything. The blower switch seem to operate on its own at times.

 

Did you disassemble the fuse boxes to check them? That's the only way to do it afaik.

The first thing to do in trying to get your blowers working is to check the brown wire at each blower connector. You'll have to remove the lower kick panels on each side to get to the individual connectors. Probe the brown and it should show 12v.

This wire is live at all times even with the ignition off.

If you have power on the brown at the connector, report back and we'll take it from there.

Larry

 

Hi skertz,

First of all, please use your Control Panel to edit your signature and add the year and model of your car so we don't have to continually ask. Not all XJ40s are the same so you'll get more accurate assistance if we know your model year, model, and engine displacement. It can also be helpful to know the mileage on the odometer.

I don't have photos to fully illustrate Larry's instructions, but hear are some of our '93 that may be helpful:

Knee bolster removal:
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Photo 6 in this album shows what you can see of the passenger side blower motor housing before you move the relay modules out of the way:

Welcome to Jag-lovers - Members Photo Viewing Page

If you never had much airflow to begin with, it is likely that one of your blowers was already dead and only one was running, and now that it has also failed you have no airflow. The system is designed with one blower fan at each end (right and left sides of the dash), each fan blowing toward the center of the dash. The two opposing airstreams pressurize the ducts and force air out of the vents. When one fan dies, this opposing force is lost and the airflow becomes quite weak.

Please do the checks Larry recommended and let us know what you find. The members here will be glad to help.

Cheers,

Don

 

1994 XJ6. I will attempt the testing of the brown wire in the morning.

 

I found the wires going to the RH blower unit. No voltage at the brown wire. Unable to check the left. Btw found two relays inside the consile by radio on left and right while taking out climatw module. Can not locate these in the manual.

 

OK. If the brown has no breaks in it from the connector to the back of the fusebox, (unplug the connectors at the back of the fusebox and check for continuity) it is almost certain that the fusebox top circuit board has a cold or cracked solder joint at the blower fuse location. As I mentioned earlier, this will be at the centre of the PC board, where the board is subject to the most flexing.

This issue is very, very common on 94MY xj40's. A simple re-flow of the solder will correct the problem and I can almost guarantee your blowers will work properly once again. You must dismantle the fusebox to do the soldering and you should repair both footwell fuseboxes as they both suffer the same problem.

Good luck,

Lawrence

 

Hi skertz,

Below is a link to a photo album that may be helpful in following Larry's advice regarding the fuseboxes. I would also recommend that you service the center console fusebox while you're at it. I found cold solder joints in all three of the fuseboxes on our '93 and some odd corrosion in the center one.

Welcome to Jag-lovers - Members Photo Viewing Page


Cheers,

Don

 

Pepsi syndrome Don?

Larry

 

Diet Pepsi Syndrome....

 

Tried a different climate control module, same issue. no blowers. Tested the brown/blue wire to the blowers, no voltage and schematic show these come direct from the fuse panels as hot. Did not disassemble the fuse panels as they tested voltage at the fuse for the 20A air-con in both position left and right at B4. But no juice at the wire going into the right blower. Still trying to clear the junk out of my way to get both blowers out to insure I'm testing the correct wires. Will try again after work tomorrow. Limited daylight now and winter fast approaching. I do notice in the schematic that there is one shared connection between the two as an orange wire coming from the climate control ecm.

 

If you have cracked joints in the fuse boxes the fuses will still show voltage across the fuse, so that test proves nothing!

No power on the brown = fuse box defective or broken brown wire!

Larry

 

skertz - when my blowers quit I too thought it was a "central" problem as how the heck can both go off at the same time if the power is supplied "individually" - logical, right? - but, there's another possibility.

Don explains:
This is what happened on my car. Only one had ever worked since I got the car and because I didn't know that, I assumed it was a power fault from a single source.

When I started to try and get the blowers going again I, like you, pulled the contol unit and even unnecessarily replaced the microswitch before finding a post over on Jaglovers from a guy with a 94 who'd resoldered the connections in the fuse boxes. After finding no power on the brown, I opened up the fuseboxes to have a look.

I started with the driver's side fusebox. I was still skeptical when I took out the unit because it had those nice clean unbroken jag stickers and looked like it was brand new. I'd checked the fuse at the front before I took it out and it showed 12v too. After taking off the plastic housing the circuit board also looked super clean and after a cursory inspection (without glasses!) decided it was fine and reassembled it into the car.

I think it must have been the following week that I pulled it out again and (this time I did have my glasses) spotted the cracked joint.
Reflowed the solder. Power was restored to the brown and the driver's side blower fired up.

The passenger side had exactly the same problem and when it came to life I was relieved to see it worked on all speeds - the driver's side was stuck on high, but that's a whole other story.

Keep at it, you'll fix it


Larry

 

The brown/blue wire to left blower hit right at blower and at right no juice. This all with ignition off. I take apart the right fuse and see nothing wrong all solder looks good. Put back together. Still no power to right. Turn on key and wow. Right blower working. Only worth key on. Left blower nothing. I suspect that left blower bad. I think right is wired wrong because i don't see s Brown/blue wire going in the blower but back a ways that does have power even with key off. I have had times where i have no climate control and radio after turning into ignition. And then sometimes it does. Not sure if i jarred something with fuse box our my ignition is at fault. I am convinced the left blower is just dead now that right is on and non left.

 

The unit worked one day and then died again as expected because I never really "fixed" anything. More investigation has shown that I now the pin on back of the fuse circuit board that correlated to the blower and the fuse at B4. Supplying power to the board and all pins are 12.6V and sit steady. Then the pin for the blower. Constant fluctuations between 2 and 4V. never steady. Turn the key and 0V. Turn key off back to fluctuations. Then muck around looking, squeezing and reassembly and get 12.6V. Then nothing and back to 0V with key or 3 something no ignition. I have found this same voltage on one side pin that goes between the two circuit board wafers on the outside. I'd be interested to see if someone could supply power to their board...put in just 1 20A fuse at B4 and test all the interconnects (the outside edges) to see if they should all be 12V

 

FIXED. It was the yellow relay DBC 10009 under right dash. This is the auxillary power, side light power and cigarette. I have notice times when climate control and radio not work after starting car. would usually turn car off and on. It was not the ignition. Also, my side lights an tail lights work about 10% of the time. Got pulled over one night a year ago so I always just leave the rear fog light switch on which suffices (but unfortunately not for the side markers). The blower receive their power from this AUX relay too. A few taps of a screwdriver handle and BINGO. lights on. Same if radio goes out. Used this electrical guide to narrow down all issues: http://www.jagrepair.com/images/Auto...ec%20Guide.pdf