chas_c, I've had problems with my '98 xk8 tilt up/down since I bought it in 2006. Been changed many times. Last time I found a motor from an XJ. The motor had the same ID number as the one in my XK. Worked perfectly for a couple of warm months. Now on a cold morning it will not drop all the way to the set memorised point. Removing and reentering the key will then let it drop the rest of the way. I think there must be a voltage requirement that the motor doesn't get at lower temps or there's something in the key lock that doesn't work when voltage is a little low. Just another thing we have to deal with. If you search the forum there are a number of "fixes" that work for a liittle while. Oh, one of the replacement motors was brand new installed by dealer. Jack

 

I felt the need to reheat this post, not least because I have similar issues.

Memory pack seems to work but seems to store multiple positions...to me indicates different issue.

Auto park steering very erratic so is this the ignition key point or motor? As I can get the movement from all axis after a while.

My point is, the thin washer is there for a reason. How can it be that you just remove it? It wears and bends and buckles. Some have experienced post removing the offending washer, the gears jam or lock up.

Lubricate the mechanism-yes. But replace the washer/spacer with a new one. Surely this will retain the integrity and tolerances of the original design.

So where can we get that replacement, what are the specifications? Calling on engineers out there...

 

My opinion is that we will not be able to come up with a permanent mechanical fix because the root of the problem is electrical.

These motor drive circuits are current limited and shut down to prevent smoking and fire in the event of a component failure. The problem appears to me to be that the sensitivity level of the current limit circuit is set too low and was not designed to allow for the additional friction from aging of the mechanism.

I think the long term solution will be a black box that which re-drives the motors with a properly designed circuit. Hopefully TheJagWrangler will get to it at some point in his busy schedule

And yes, I am an engineer.

 

By day, a mild-mannered engineer. By night, the JagWrangler! Fighting the evil spawn of the sons of Lucas.

 

Mish-Mish,
Thanks for the very informative instructions.
Mine has been acting up in the cooler weather as described in your earlier post.
I will be doing the washer removal in the near future.
Thanks again, Dave B.

 

Ok so you remove the washer and get short term benefit until the gears jam.

Why is the washer there?

If your adjustment works on all axis but doesn't with auto then cleaning and regreasing and cleaning or replacing the electric connector that fits to base of the barrel should do it.

If you can't get movement then it's the tilt unit.

Next time you work on the brakes try leaving out something because it's difficult or gets in the way. Come on...this needs to be approached in a sensible manner don't you think?

Like I suggest, that washer is there for a reason.

 

Mish-Mish,
I had a chance to work on my XK8 last evening.
I removed the spring washer, lubed the gears and cleaned the potentiometer.
The weather is cooler today and my Tilt works flawlessly.
Prior to this service, I would have to bump the knob to get the steering wheel to lower to the preset position.
Even if I have to do the lube and clean procedure every year or so, it's not that big a challenge.
Thanks again for the info.
Dave B.

 

Burdedw. Now that you think the tilt is fixed.........wait. At some point in the future it will stop operating properly. In a previous thread of mine I descibed my surefire cure. Forget removing motor, lubing, removing washers. None of these is a permanent fix. I've lived with the tilt problem with a simple procedure. Take 3 extra seconds to start you car. Insert key....DO NOT TURN IT....now wait for wheel to drop into the set position. If this doesn't happen remove key......wheel should not move.........reinsert key.......wheel should drop to memorised position. This has worked everytime not only dropping down but also when you turn off the car and the wheel lifts. Jack

 

Although there maybe an overload sensor in the control unit I believe if the potentiometer detects no movement it cuts the power. My up & down gearbox is broken, the plastic worm wheel is damaged probably due to previous owner using the steering wheel as an access/egress aid! I stripped it and blew out the broken bits with an air line and it worked a couple of times then jammed. I would the wheel up manually, refitted the motor and disconnected one wire to stop accidental movement. Looking for second hand motor now....

 

Hello,

I have not worked on the steering wheel potentiometers yet but spent quite some time on the seat potentiometers.

The best way to test the sytem I believe is to connect a voltmeter betweeen ground and the tilt potentiometer feedback (one of the 3 wires on the potentiometer).

Check:
- that the voltage increases/decreases continuously during all the time while the column is moving up/down (not sure if up = voltage increase and down = voltage decrease or vice-versa)
-> if at any time the column is moving, even slightly, but the voltage remains constant:-> if at any time the voltage is getting too close to ground or to battery voltage: the potentiometer range needs to be ajusted. On the xj8 seat potentiometers, the voltage should remain in the [+1V min; +10V max] range. If the voltage is getting to close to 0 or 12V the system is impredictable. I believe it may have to do with the need to convert this analog signal to a digital signal (ADC) within the BPM in order to be compared with the stored memory position. This requirement is detailed in service bulletin 501-35 for xj8. I could not find the same adjustement requirement for the steering tilt potentiometer, maybe because this potentiometer is not available as a stand alone replacement part like the seat potentiometers, but service bulletin 501-51 for xj8 and xk8 lists the potentiometer out-of-range as a possible root cause not only for seats memory malfunction but also for Easy Entry/Easy Exit malfunction. Nonetheless, I would bet that a similar requirement exists for steering column. There may be different ways to make this adjustment. On the seat potentiometers there is a little oriffice that is accessible with a micro flat blade screw driver with the potentiometer in place in the car. If the same oriffice exists for the column titlt potentiometer, you should position the column to one of the extreme positions (fully up or down) and check that the voltage stays in [+1V min; +10V max] range. If not, turn the screw driver to move the potentiometer back into the autorized voltage range [+1V min; +10V max]. Another method without the little screw driver suppose to disconnect mechanically the sensor from the motor, turn the sensor by hand to bring the voltage back in range, and reconnect it to the motor and check again the full motion range versus authorized volatage range [+1V min; +10V max].

 

I just ordered and received an IDS so I have now another way to test these potentiometers, here is the steering Wheel reach potentiometer curve, the up and down curve is much more jerky which make me think of a dirty or worn potentiometer track (issue is definetely temperature dependent).

 

AHHH, It must be hard having to live in Juan de Pins and drive a Jaguar......

 

French are known to always complain, so I won't add to the litany this time .

 

By the way I succeeded in capturing the defective axis (steering column up/down) potentiometer feedback. See how the curve is jerky:





I took my screw driver and was on my way to pull out the up/down motor and its potentiometer when I noticed the potentiometer was just not clipped properly on the back of the motor (probably as a result of my previous intervention to fix a noisy air conditionning/heater blowing fan).

I pushed the potentiometer until I could clearly hear the clip and it was sitting flush against the back of the motor. My steering column is now travelling smoothly along all the range.

 

1998 XK8. Performed procedure this week and steering movingwith no issues. Thank you so much forthis awesome thread. Just as a note, whenremoving the under scuttle be aware of the length of wiring harness toswitches, i.e, in my case I ended up inadvertently pulling wires out of valetswitch when the under scuttle all of sudden released when pulling it back. Easy fix for the valet switch even though don’tuse it. Thanks again.

.

 

will the up and down tilt motor from a 2000 xj8 fit and work in my 1998 xk8??

 

Has anyone found a replacement potentiometer.

I clean mine a number of years ago. I don't use the car much so it didn't bother me too much. This is the same type of problem with the TPS I had back in 99. Finally jag had me stuck where I had to buy a new throttle body to fix that problem since they didn't sell just the position sensor, similar problem, dirty contacts.

 

As one of our members pointed out, exercise, exercise.


I was apprehensive to touch my adjustment as the results were just as you described. Move a little overload and stop.


While est, driving, I kept adjusting the column as far as it would go. Now the wheel adjusts all directions without a problem. Like the bod, exercise.


I found a similar trait of the XK8 with the front roof hydo latch. Excessive pressure required to move the lever. I flipped the lever upside down for easy smooth operation. My Theory. Could be the cause of header green showers. So far the front latch has not open by itself. Tks REB

 

Today I tried doing the suggested repair to the up down motor on my 2004 XKR. I had all the typical problems and nothing short of either trying the repair or spend anywhere from $520.93 to $599.95 for a new motor. At those prices I chose to try the suggested repair first. When I pulled out the motor I could tell tell that there was too much of a bind on it and it was putting stress on the motor. So it was taken out and taken apart taking out the spring totally, cleaning the nylon gears, and replacing the grease. After that it was reinstalled and has worked as it should. In-fact it now works so well you can not hear the motor when moving up or down. You can still hear the other motor when it goes in and out. It probably could use a little cleaning and grease change, but since it is working fine and it's removal is more complex it will be fine for now.

 

It seems I have fixed mine also by just cleaning the old grease from the gears and re-applying new silicon grease.

I have tested the potentiometer and it is just fine, no signs of jumpy ohms readings when turning it. I am pretty sure the noisy curve I have captured with the IDS (see above post) is the result of the old dry grease that makes the gear set to oppose a static resistance, and then suddenly release the constraint and moves a fraction of a turn, then oppose static resistance again, etc.

By the way I have noticed the mechanical range of this potentiometer is such that it does not reach the minimum resistance (0 ohm) nor the maximum resistance (2.2 kiloohms) but stays in the range 200 min to 2000 max. I believe this is an improved design (with respect to seat potentiometers that reach min and max resistance). Why improved? because unlike seat potentiometers, they do not need to be mechanically adjusted because by design they are forced to stay in their linear range (and indeed they do not have the little hole that the seat potentiometer have for adjustment).

Why does seat potentiometers need to be adjusted when de-assembled (there is a service bulletin for that): because when potentiometer reaches min or max, they are not linear, they may stay at 0 or stay at max for a while when they are turned away from their extreme positions and the car electronic thinks there is an issue (motor energized and portentiometer not changing value) and stops the motor. I believe the same rationale drives the failing mode of our steering up down motor: if old dry grease produces to much static resistance, the up/down motor shaft makes a few turns, build up static constraint in the gear set, then the electronics see no change (or sudden implausible change) in the potentiometer value and stops the motor.

I have left the spring in my repair (just changed grease). I believe the spring is there for something that is to reduce the play in the gear set with 2 benefits: less play = more accurate return to the memorized position, less play = stay away from the critical situation where the motors makes a few turns and the electronic sees no or implausible change in potentiometer value and stops the motor.

I have been able to remove the potentiometer at the back of the motor while keeping motor in place. The potentiometer case can also be opened in place (and not having to disconnect wires or cut the cable zip tie). So basically I am able to pull out the gear set in a couple of minutes and almost no tools doing this way.