1988 XJ40 heater motors

Does anybody know of a way to test these before removing them from the car? If so, can you post me the answer,alternatively,can someone tell me the procedure for doing so? Thanks Phil

Reply to
Phil Morgan
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Phil, I assume you mean the blower motors for the heater? What exactly is it you want to test? You have two blower motors, one in either foot well of the car. Simply pull the fuse out of the fuse panel on the right side, turn the power on to the ignition and test to see if the left blower is working and if it has three speeds. Put the fuse back in and do exactly the same thing by pulling the left fuse. If both blowers are working then you do not have a problem with the blowers. If the blowers are working on HIGH only (or defrost) then the resistor or the diode is blown on that particular blower. You can either buy a new blower assembly or search the archives at

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or read the XJ40 book at jag-lovers where they tell you what parts you need to buy and how to fix the units. The cost to fix the electrics on both blowers runs about $5. If the blowers are both working on all three speeds, but you are getting no heat than you have a stuck damper solenoid in the blower box. This means pulling out the blower box from the dash and doing repairs.

Webserve.

Reply to
webserve

Thanks for the info, unfortunately, BOTH blower motors are non operational and when I try to turn them on they blow BOTH fuses in fuse blocks 1 & 2. Heat gets into the car more through 'osmosis' than by design! I think I will have to 'delve' into the underdash area and pull the motors,or??? More help appreciated! I am trying to make this wonderful car my everyday driver. I am lucky in so much as I have several 'parts cars' in my yard and so I can canibalise what I need from these donor vehicles. My next job is to try and source the reason for my intermitent brake assist,and the constant warnings on the vcm of 'low brake pressure' & "abs failure'. I have been lucky with JAGUAR as they agreed to perform a long overdue recall on the brake system, recall D348 which addressed the switches from the back of the brake thingy near the green reservoir, that shows red all the time! I am a mechanical Luddite and all help is greatly appreciated! Thanks again, Phil

Reply to
Phil Morgan

Mine (1990) were not blowing fuses, but they weren't blowing air either - just plain did not turn. Drained a few pints of water out of the system - bottom of the fan housings.

I have the driver's side - left - one out now and have fixed it and have not yet gotten it back in - waiting for warmer weather.

The electronic controls seemed okay - not corroded away - so I pulled the fan motor out and checked the brushes. They looked okay too, but there was a certain amount of guckiness around the brushes and the armature, so I cleaned that all up - ran a needle along the grooves and polished it with a very fine emery cloth, ran it up a few times with the battery in the house, works fine.

As I said, I haven't reinstalled it, but I went out to the car and plugged in the electric connections and it works fine on all speeds. I'll get it back in then pull the other one. Wish I had a heated garage.

- Tom

Happy Trails To You

Reply to
Happy Trails

Phil, You have now entered into the repair zone!! In order to determine what is going on, you will have to do some pretty intense work on the car. It can be done as long as you work patiently and keep track of how things came apart. My FIRST suggestion to you is that you go to your local auto parts store and purchase a Haynes manual for the 1988-1994 XJ40. The information and pictures are most helpful. Then I suggest you print out and read the XJ40 online book at

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There are alsogood photos here and it is written by those of us who have been there --done that. Since you are in Canada, the chances are you drive a LHD car sothe passenger's side is on the right. I suggest you pull the blower on thepassenger's side. Most likely there is water in the blower causing a shortbut you won't know what is going on until you pull a blower and check therelays and the motor. The Low pressure and ABS lights are a different matter. Low brakepressure is referring to the Green fluid in the car. It runs the brakeassist and the self leveling rear shocks (SLS) if you still have them. Ifyou have the SLS, you most likely have a leak in the system and they need tobe replaced with standard shocks and springs. If they have already beenremoved then you may have a leak else where. If the SLS has been removedthen the system is running ONLY the power assist brakes and not powersteering as in the 1990+ models. Chances are, the hose that runs from thegreen plastic reservoir needs to be replaced. It is exposed to constant heatand pressure and gives way. Before it goes totally, the green mineral oilbreaks down the rubber and the hose will constantly weep. When you startthe car with a full reservoir in the green tank, you should be able to raisethe RPMs on the engine and make the low pressure light go away. If thereservoir is full and the light does not go away, you may have a problemwith the motor driven pump on the front of the engine. This is fairlyunlikely as I have only heard of 1 or 2 of these pumps ever failing. The ABS light, on the other hand will drive you crazy trying to fix.You need to determine if the light is real or simply a "Gremlin" like thebulb failure lights. The ABS light can be cause by any number of items.Mostly are any one of the $250USD sensors on any of the 4 wheels. There are3 times the ABS light will activate. The first is upon initial start-up. Ifit comes on and stays on than you most likely have a broken wire or othercomponent that is not making a complete circuit. With the low pressurewarning light as well, you will have an ABS light that comes on when you getto 5KPH. The computer does it's second system check at 5KPH. If thepressure is low or the sensors are not reading properly than the warninglight will come on. In this case, I believe your low pressure could becausing the ABS light. On my '88 XJ40, I have to run the engine with the carin Park until the low pressure light goes out. Then I never see the ABSlight again during the trip and the low pressure light comes on every time Ihit the brakes. If you are intending to use this car as a daily driver, there are 2 repair parts that I HIGHLY recommend you keep in your trunk at all times. The first is a $75 sensor called a CPS (Crankshaft position sensor) It is located on the front of the engine near the lower pulley. These sensors have a tendency to give very little warning when they go and they WILL leave you stranded. This is not just a Jag problem by the way -- most modern cars have these sensors. You need to keep a 5mm Allen wrench with it in order to change it out. The other item is a 9 to 10 inch radiator hose that runs from the water pump to the water rail UNDER the exhaust manifold. It is constantly under terrible heat conditions and I have had two of these hoses go in a period of 4 years with my XJ40. They are an inexpensive item at about $10, but rarely do parts stores carry them so if you blow this hose, the car is sitting where ever the hose let loose until you can order and get a new one. Get new Stainless steel clamps for either end as well. Do some analysis on the car after you read the books and you should be able to point to the problem a bit better

Webserve

"Phil Morgan" wrote in message news:4Z6Wd.49934$ snipped-for-privacy@news20.bellglobal.com...

Reply to
webserve

One common cause of the "ABS light on all the time" is a faulty ABS relay module in the trunk. Pull it out and pop the plastic cover off. Carefully inspect the solder joints where the mechanical relay is soldered to the circuit board and re-solder them if they look fractured. Bad self leveling shocks really shake things around back there, but in my opinion, heavy relays in shock/vibration environments should not rely solely on solder joints for attachment.

-jk

Reply to
jk

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