Oh Boy what have I gotten myself into?
Today I dug deeper into the "top not latched" problem on my 2002,XK8. I decided I really couldn't fix it until I determined what had been done to it by the last owner. So, out came the rear seat, and the top of the rear quarter panels. There I traced a pair of wires into the console. I found out that someone has completely taken the BPM out of the equation by running the wires directly to the relays that operate the pump. They also ran wires to a toggle switch that raises or lowers the rear windows at will.
Now to be honest, I would probably be happy with that, the top goes up and down just fine. But the constant "top not latched" message is too much to ignore. I then decided to see if I can get the message to go away with the top down. That only requires one switch on the right hand ram to "tell" the BPM that the top is down. I seem to get a constant ground signal from that switch, top up or down. So now I need to figure out how to physically access that switch. Has anyone else had this experience? How do I get a look at it?

 

The pump motor is floating electrically until brought into play by one of two relays, which make it pump in one direction or the other. You need to apply B+ to one lead, ground to the other to make it go.

Recommend you disconnect the pump's electrical connector before testing it. Connector is next to the pump, two wires, black and white. Requires some effort to get it open.

 

Man, that's a new one!

I would suggest using the schematic to turn the wiring back to the factory state.

As far as the switch in the ram goes, unfortunately that is sealed inside the ram and is not really serviceable except perhaps with a ram rebuild or a ram replacement. Double check that this switch is really bad with the wires disconnected.

 

I agree get the wiring back to normal, who knows what they did and why. As for the ram I know that the hydraulic components can be rebuilt but not sure if the electrical switches can be repaired I would call Top Hyd to see if they can. I do agree with Steve in verifying that the switch is a problem first. You begin to wonder why people purchase a car like this and manage to do repairs like that.

 

The pump is reversible under control of the BPM. Sometimes white is B+, sometimes it is ground.

 

I wouldn't rush to restore 'factory' wiring unless you intend to replace the top latch hoses.
Also if the ram limit switch IS kaput you've got an expensive rebuild before the BPM will work.
You've got independent control of the rear windows which many people have done as a mod and also the main ram function is OK
All you need do is spoof the BPM to get rid of the message and (as I understand it) you're happy.
There's no need to do anything dynamic - since the BPM never sees the top up/down button once you've convinced it the latch is locked it will stay forever in that blissful state.
If the 'convertible latch closed switch’ and the ‘convertible top closed switch’ are closed the BPM will think the top's locked.
You can achieve this by grounding the relevant pins on the BPM, no harm done and easy to undo if required in the future.
Pins 89 + 62 sense those switches.
You may need to ground 36 which is the 'ready to latch' and the lift cylinder switches in series.
If the message doesn't go away try a hard reset.

PS if you haven't already, download JTIS for your MY and check the electrical section under 'Convertible Top' for pinouts, wire colours etc.

 

I think in this case I have to agree with Steve. I won't miss the magic of the power latch because I have never had that wonderful feature. And the top really does work well as far as going up and down. And being able to put the rear windows up and down at will seems to make a lot of sense too.
I have been going over in my head how I can "fool" the BPM and I think what you have suggested is what I will try next. Whoever did this "modification" was not an enthusiast. The workmanship sucks and it looks like they broke darn near every plastic piece that they touched. But, it does work except for the "top not latched" message. So that will be my project on Monday.
I want to thank Gus for the long phone consultation he provided recently. It is so gracious of him, and all of you who to try to help. Thank so much! I would be lost without this forum.
I will post what the results are, I hope I can help someone else for a change.

 

I think it has to work.
If the poor old BPM is really confused you may need to toggle the 'top closed switch pressed' pin and then ground the others so it gets the correct sequence but I doubt it.
Please keep us informed.
I think there are quite a few members who would happily ditch the BPM's questionable competence and DIY the top.
If you do get it to work we'll need wiring diagrams and pics of the pump mods - we can make a How-To (how to screw your BPM) !

 

Steve,

I hope you're right, but I'm less certain. Reason being ...

The documentation we have shows what should happen given a certain collection of states and events in the system ... those anticipated by the designer. But this really isn't a complete "truth table" of all possible states and events, and we're creating some unanticipated ones.

Those tests I described in #445 (big number!) above had the correct end-state, but the system didn't see it that way.

We'll see I guess.

I really do hope this all results in some sort of general method for converting to manual latch operation. If my hoses ever do fail, that is the way I would like to go.

 

Dennis,
You know much more about this than I do.
There can't be that much 'clever' in the BPM or it wouldn't get its knickers twisted.
At least pulling a few pins to ground won't cause disaster.
Once Lanny has the BPM 'open' we can try various inputs to see if spoofing works - please help with your input.
I'd go for this if my hoses pack in.

 

Thanks, but you're giving me too much credit . I was just thinking out loud about how logic circuits can sometimes give screwy results with unanticipated inputs. Here's hoping I'm tilting at windmills ...

 

Boy, I HATE to give up! It is in my nature to fight until I win or can't fight anymore. But,there is also wisdom in picking your battles.
Today I started by tracing all the extra and disconnected wires in my car,wires that someone had added or modified. I am glad I did that, there were bare wires everywhere, some that connected directly to the battery, with no fuse. None of the wires were soldered,just twisted together. So I spent the first couple hours cleaning up that mess.
Then onto the main issue, kill that "top not latched" message. I am afraid Dennis is onto something when he predicted it would not be as easy as grounding a couple wires. I used the plug at the header for access to the signal wires. I carefully skinned back the insulation a little bit and soldered some pig-tails onto them. Then I used a jumper wire to ground them. I tried grounding all at once, then I tried using a sequence that I thought might mimic what the switches would do. I tried a hard reset between each attempt. In a last measure of desperation I traced the wired from the header to the BPM plug, just to make sure they were not cut somewhere. All checked out. I am running out of ideas.
The two wires that used to go to the BPM from the top switch on the console are just cut off and laying there. Is it possible that the BPM needs a "prod" from them to run through a routine or something? I admit, I am just guessing here. Any help will be appreciated and praised in the highest places

 

I still think your path to happiness is to repair the car back to it's factory configuration. This is coming from a guy not afraid of electical mods.

 

I agree with Steve. This is going to be a mystery car for you and trying to adjust someone else's modifications to provide you the operation you want is going to be a nightmare. Put the system back to normal and then begin your testing.

 

Well, at least I got to see how my car is put together, considering I took out about half of the interior. If I decide to try to restore the original factory operation I will know what to expect. And I am cleaning up a lot of dangerous wiring and replacing a lot of missing fasteners. If it sounds like I am rationalizing the hours I spent only to end up with the same problem I started with....your right. Maybe if I get a chance to really fall in love with this car I will take the plunge and try to restore it as it was. Meanwhile, I guess I will just live with the "top not latched" message.
It is a shame that there seems to be no way to get away from the hydraulic hose issue. If there is a failure that requires you to raise your top manually, do you still get this message? Has anyone out there done this?

 

Many people have gone 10 years on the original hoses. Yes, it is a problem, but it tends to get a bit overblown by the unending dicussion on the forum.

 

Lanny,
Don't give up yet - there's nothing to lose but a bit of time. You've got all the pins 'on tap' and you can't blow up the BPM by grounding them.
Try grounding pin 63 - 'Open Top Switch' first - You don't get the 'Not Closed' message when the top is opening or down so that might be all it needs.

If that doesn't work ground “Top Latch Closed” Switch Pin 62 first so it thinks the top is closed, then pin 63, then open 62.

If not it will probably be necessary to ground the 'close top switch' pin 10 on the BPM and keep that grounded then sequentially ground the other pins.
The order (from the bulletin) is

“Top Ready to Latch” Switch Pin 36

“Top Closed” Switch Pin 89

“Top Latch Closed” Switch Pin 62

All three must be grounded at the end of the sequence.

Obviously ignition needs to be on !!

No, you don't get an error message manually closing the top so manually 'activating' the microswitches by grounding pins should work.
Should......
Can you confirm you've still got a defective ram limit switch now you've tidied up?

 

Good morning Steve,
Thanks for the encouragement. I am not aware of pin#10,I guess I missed that. I will look into it again. I am working off of a schematic for my 2002 model. As for the defective switch in my ram, I am not so sure that was real. I have determined that when my top goes down the lower switch does work. But after a few moments the top "relaxes" a little bit and the switch goes back to open. I don't know if that is a problem or not,I suspect not.
I still have the header connector exposed,so I will try the sequence(s) you suggest before I button it back up. I hate to give up, but I have other issues to address and after several days of no progress I am becoming a bit frustrated.
Yesterday I accessed the original wires in the console and grounded one or the other wires momentarily. I got the chime sound,so the poor old BPM still thinks it in the game.

 

Lanny,
Just check your BPM pinouts - I've got a diagram for a 2004 and would hate to give you wrong info.
Do try a 'pretend top down' first - like you I don't like being beaten by (probably) inanimate objects.
Good luck and, of course, the Top Force be with you.

 

I am sure a manual operation can be done but trying to do it after another hand has modified the system will only make it a lot more difficult. I still feel putting it back to normal is the right thing to do at this point. If you need an electrical diagram I have them on my page.