Hi, everyone. I hope someone can help me, and I apologize for how long this post is. I have a 1998 XK8 convertible, with only ~50,000 miles on it. (I bought it used, with 16,000 miles on it, in about 2003, I think, and I usually drive a 2nd car.) I moved to Baja California, Mexico ("B.C.") with it about 5 years ago, and I almost never drive it now, due to awful road conditions, and to the fact that mechanics here cannot deal with the car. (But I plan to move back to California within a year, and no way will I part with the car.)

Before I moved to B.C., a few warning lights started coming on, periodically, for no good reason: Engine Coolant Low, ABS (rarely) and the "Brake" light. Not much later, the "Low Brake Fluid" warning started coming on. Two mechanics in B.C. and one in Chula Vista, CA all failed at fixing them, and I tried to ignore them when (rarely) driving the car. Then, about a year ago, more problems occurred: the "Passenger Door Open" light came on most of the time. Probably in connection with that, the overhead lights would not go off, either when the car was running or when it was off (until I removed them, because they were draining the battery). The windows would go down a bit, upon opening the driver's door, as they should, but they would not go back up automatically. Sometimes, when inserting the key in the driver's door, the windows would go down, also. And the automatic key failed to function.

One more problem: one of the inept mechanics in B.C., when trying to fix the above problems, told me that my driver's seat recliner was broken. He had put the seat all the way back, and it would not return. He said he spent a long time repositioning it, but that I should not put it all the way back until it was repaired.

I was going to give up and take the car to San Diego, to a Jag specialist, when a car detailer managed to put the driver's seat all the way back, rendering the car undrivable to such a distance. So, I took it to the local, trusted (relatively) mechanic. He claimed he could fix everything, and since labor here is cheap, I told him to give it a try.

Here is what he and someone he knows who specializes in electronics said. (The prices he quoted are his actual cost of used parts, ordered from a Jag dealer in California, and I am sure that, even for retail used parts, they are overpriced. I found some on ebay for half these prices.) He said I need the following new parts:
1) Driver's seat module ($550). (Makes sense to me.)
2) Passenger seat module ($450). (Makes NO sense to me. He said this was associated with the "Passenger Door light" problem, but why would that not be related to the Passenger Door Module, if any module at all?) 3) Body Processor Module ($600!) He said this was responsible for the other problems with the lights.

The car also has a small oil leak, which the mechanic says is due to a small hole in the transmission oil pan and leaky gasket. (Pan, gasket & Filter kit: $230.)

His labor cost is only going to be $150. (Mexican labor is cheap.) The total cost, using the Jag Dealer's parts, would be $2,400.

It is worth it to me to take SOME risk of buying a part that is not needed, if ultimately he can fix the car, because if I take the car to San Diego, just the cost of diagnosing the problems would probably be several hundred dollars. However, I don't want to waste a lot of money and time (if I order the parts, I'll have to order them, wait for their delivery to San Diego, and probably go to San Diego to pick them up) - and have the car still not work.

I would appreciate comments on whether the recommended fixes seem to make sense.

Thanks much in advance!

Nicole

 

The most common cause of multiple error codes is a weak battery. Charge and load test or just replace with a new one.

The seat modules can be rebuilt by Darrell Turner, and I would hold off on the BPM because I believe it might be okay, and I believe special Jag software has to be used when replacing it.

https://www.jaguarforums.com/forum/x...dation-103908/

 

Lots of questions here, but two main issues I will try to address before the real experts show up with better answers.

The warning lights can be brought on by many things, some unrelated to the messages. Try two easy & cheap things to try first:

1) do a hard reset at the battery (pull negative cable from battery and touch for 15-20 seconds to positive cable connection). See if the warning lights go away, and stay away.

2) if the reset doesn't solve it, have your battery checked. Even a minor drop in voltage from the battery on these cars will cause a multitude of faults to appear. A new battery is often the cure.

For the seat module, try taking the passenger module off and swapping it with the driver's side. If it solves the problem, it is the driver's module.

Plenty of threads on the forum regarding seat fixes. The wiring can get caught and cause shorts as well. Do a search.

If you do these yourself, they are all cheaper than even labor in B.C. Good luck.

 

I can see why the labour is cheap.

When the vehicle is being used infrequently and then only for low mileage, it's essential to have it sitting on a battery tender. A partially discharged battery is often the cause of weird electrical gremlins. The windows dropping but not going back up automatically is an indication of this.

I'd get a good battery on it before throwing any money at the suggested parts. Not saying you won't need attention to the modules but get the battery sorted out first and you could be pleasantly surprised at how many things this fixes.

Graham

 

Trying to help with what I have encountered:

For this, there are several threads on this forum already. Check the ABS sensors on all 4 corners. They typically need to be cleaned (once the wheel is off, it is just 1 bolt). Worst case, the electrical wiring to the sensor has intermittent connections, and the computer throws a fault. If you had a code reader, it would tell you where the problem is. Folks have reportedly repaired these wires with soldering at the sensor end.

The brake switch is also a known source of issues. If you have "Check Rear Bulbs, Cruise Control Not Available", more than likely this switch is faulty.

From your post, there is probably more to this, but you can try and reset the windows. Press and hold the "window up" button until you hear a (faint) click. Do the same on the other side.

For the seats, there are many posts as well. The short version is that the modules are interchangeable between driver and passenger side, and that the modules can typically be repaired by some forum members for a small fee. The circuit board in the module rubs on the hard plastic case and the outside edge tracks wear out. Easiest is to swap them out and see if the seat regains full control.

Best of luck, keep us posted.

 

for the windows, dome light and door open it sounds like the micro switch if a reset does not correct the issue.

See here; starting at post 6
https://www.jaguarforums.com/forum/x...roject-118210/

 

Regarding the battery: I had a new battery put in about 7 months ago.

 

Thanks FMertz (Fred?): I HAD read all about the seat modules, and I even suggested switching them to the mechanic. (That was when - OK - he had said the problem was the MOTOR and I questioned this. But he said that before the electrical "expert" looked at the car and diagnosed it as the module. It was also before I was told I needed BOTH seat modules replaced.)

I realize that there could be a million different causes of these problems, and I may well have to see a Jag specialist to find out. What I really was trying to ask was whether the suggested fixes make any sense or not - assuming that various other possible but not too likely causes were ruled out, rather than how I should figure out what is wrong. Because I am incapable of doing that, and at this point, I don't think the mechanic is going to be open to these suggestions. So, I am sort of stuck either using this Mexican mechanic or taking the car to the US (which will likely involve a long drive, staying overnight, renting a car, etc., and a big expense).

 

Thanks Jandreau. I believe the three incompetent mechanics before this one each tried resetting everything - more than once. So are you thinking the problem is NOT the body processor module? I read the post you cited. I don't think my problem is the same; there were basically two "sets" of electronic problems, each group happening at once. Too many problems happened at the same time as the window and door problem for me to think it is just a switch. And it makes sense to me that the "Passenger Door Open" light warning is related to these problems.

 

RJ237: Thanks for the tip about the modules! Should I assume that the electrical "expert" here doesn't have and cannot get the Jag software (for a reasonable price, anyhow)? I sort of assumed he had to have it to diagnose the problems.

 

Msterieus, I feel for ya bubby, you got a bucket load of issues that would make the most experanced on this fourm pull their hair out. If you can't logically tackle these one at a time than all you can do is open your wallet and bend over. Like most one night stands I expect the feeling Afterward will be less than satisfying.

I for one would not go the module replacement route at this time, while there could be module issues there are just to many simpler solutions to be investigated first.

 

7 months is just about enough time for the electrolyte in the battery to have evaporated away, if you haven't added any Distilled water. I would start by doing a stress test on the battery. Any auto parts store can do this. If the battery is good, I would then do a hard reset., by touching the neg wire to the positive wire and terminal on the battery. I would then check the voltage past the big fuses just in front of the spare tire in the trunk. From there I would check the voltage at the junction box in the engine compartment. If you have 12.7 Volts everywhere then start looking at modules. This could be corrosion on either the positive or ground wires in the car. Good luck.

 

We keep hovering around the battery. Maybe you can't have it load tested there, so just check the voltage after sitting overnight. If less than 12.4 that's risky. Then have them check it while engaging the starter. If it dips below 11 it could easily be the source of your problems.

A seven month old battery that is in a Jag that's not driven frequently for a half hour or more could be bad.

 

Rick and RJ: All problems predated the purchase and installation of the battery - some by a year and many by many years. They persisted after installation of the new battery. I just do not see how they could be due to the battery.

Jandreau: Your "bubby" comment may be right on. I have to assume that the mechanic and/or electrical guy did try all the more obvious things. The question, I suppose, is: do I bend over in Mexico (buy the parts and let the cheap mechanic replace them) or bend over in San Diego (go through the time and hassle, pay a Jag mechanic big bucks to diagnose, then possibly pay for the same parts, at a higher cost, since I will have to buy them from the mechanic). Oh well, I sure do appreciate the replies!

 

Had you originally said the problems existed for a long time, I would not have insisted that the battery is the likely culprit.

 

RJ237: I did. "I moved with [the car to B.C.] about 5 years ago. ... Before I moved to B.C., a few warning lights started coming on .... Not much later, the "Low Brake Fluid" warning started coming on. .... Then, about a year ago, more problems occurred."

 

I still think it is the battery due to the "more problems" bit.

It's a simple thing to eliminate by fully bench charging the
battery for 72 hours and doing a reset.

The poster is not doing himself any favours when he insists
here and probably to the local mechanics that it is not the
battery.

There are lots of threads here where the battery has been
the solution after much hair pulling. But, no let's not try
that.

 

I am not trying to insist on anything. I am trying to understand how it could be the battery, if the problems have gone on through 2 batteries and the computer was reset several times during the years. And no, I never told any mechanic any opinions of causes, except that, after reading posts on this forum, I suggested that the driver's seat problem could be the module rather than the motor. I am not stupid, but I am a typical female driver who knows very little about fixing cars.

If someone who understands the timing of these problems, and that the computer has been reset both before and after I put in the new battery, thinks the problems could be due to a weak battery, I'll certainly ask the current mechanic to charge the battery and reset once more. Thanks.

PS: Does "bench charge" mean remove battery and charge outside of the car?

 

Bench charge: I don't think that's essential. Charging it in the car should be sufficient. The seat back motor can be tested by removing the seat back at the bottom and applying power directly to the motor connection.

But I'm a little unclear on the seat problem. Is the seat itself moved all the way back, or is the seatback fully reclined?

 

I have been following this post and thought I would chime in on what I would do if it was my car.
I agree with most post to start with checking the battery. But I would go a little further. I would check the voltage at the power protection module in the trunk. I would check the voltage from the battery positive tower to where the negative cable bolts on to the side of the trunk.
I would then check the voltage at every fuse box and the false bulkhead.
I would have your mechanics check these points and write down the results from each spot. Don't let them say everything is good, tell them you want to see their results.
I would start the car as suggested earlier to see the voltage drop when cranking.
Then get a reading of while the car is running to see how it is charging.
Check all of the ground points for corrosion and loosen and tighten to make sure you have a good ground.
Like stated above with all of these issues it sounds like an electrical issue.
The only other thing I can think of is moisture and corrosion at the module connections. I think multiple module failures is extremely rare unless something happen to the car.( flooded or rained on with top down)
Since labor is cheap I would check these things. They are not to difficult to do and if you come up with a problem somewhere you won't be blowing you money on a lot of parts.
I would report back to the forum with the results of these test and maybe we can help you from there.
These are just my thoughts if any member thinks I'm in error or have any more suggestions please do.
Good Luck.