*ist D Grip problem

Most definitely battery grip. Prone to a phenomenon know as 'flexing'. The contacts on the grip fail to connect to camera's contacts. Can cause other problems such as switching on and off when you least expect it. I got sick of going thru about two grips for every camera so went with 1D/1Ds series. You'll hear people say 'stick with Canon grips' blahhh(!) too ****** expensive and are prone to the same problem. Can't be helped when you hand hold a camera+grip for long periods - the warmth of your hands can heat up (warp) the plastics and it's all held 'together' by one little screw in a tripod mount (!)
You could 'try' removing the grip, leave it off for say a week. I don't know why it's how, but if always works like new when you put it on again. Until....it starts playing up again. :)
OEM, 3RD party... OTY. For the price of one Canon I could get two cheapies. Always had the 1D (classic) and ahem...still have it! So I stuck with the series (1D IV, 1Ds2) Still holding onto my 7D w/grip (3rd party) though.

I understand there isn't a manual, just a quick how-to guide. Here's some basic use info from a review
http://www.the-digital-picture.com/reviews/canon-bg-e6-battery-grip-review.aspx

The Canon BG-E6 Battery Grip is designed specifically for the Canon EOS 5D Mark II as shown above with a Canon EF 16-35mm f/2.8 L II USM Lens mounted. To get the Canon BG-E6 Battery Grip into the position shown, the LP-E6 Battery is removed from the 5D II and the battery door detaches. The BG-E6 slides up into the battery compartment and locks into place via the tripod socket screw seen on the BG-E6 just below the lens in the above image. The BG-E6 provides its own tripod adapter threads - this functionality is not lost.

The Canon BG-E6 Battery Grip holds two Canon LP-E6 Batteries that deliver double the number of shots or video time from the 5D II. Alternatively, use 6 AA batteries in the included Canon BGM-E6 Battery Magazine shown below.

This is an old post but if you haven't found your solution yet here is the solution.
The Fuji FinePix S2 Pro uses two sets of batteries one set located in the camera body grip and another set in the battery grip itself. If you are experiencing the problem you are then the batteries in the camera body are dead and need replacement. here is a diagram. Replacing the batteries in the camera body require removing the grip.
Diagram

I'm sorry but I can't send a diagram via this site. I have no idea where I can get a diagram either.

But, to replace the throttle grip on your Softail, you'll see the not only are you replacing but you're replacing the throttle sleeve as well. This actually makes it easier.

To replace the grip, first loosen the throttle and idle cables as loose as you can at the adjusters close to the throttle grip. Then remove the screws that hold the two halves of the throttle switch housings together. Carefully seperate the housing halves as much as the wires will allow.

You'll see the cables coming up and connecting to the throttle sleeve. Each cable will have a ball and a ferrell on it. Work both cables loose and slide the throttle sleeve off the handlebar.

Now, lubricate the inside of the new throttle sleeve, the cable area of the throttle sleeve and the handlebar with fresh white lithium grease. Slide the throttle sleeve up on the handlebar and work the cables back into the throttle sleeve. Be careful not to lose the ferrells. They must be in there for the throttle to work properly.

Once you get the cables installed into the sleeve, put the switch housings together and install the bolts. Before tighten the bolts slide the throttle up onto the handlebar until it stops. Then back if off about 1/8 to 1/4" or so. Tighten the bolts. Readjust the cables leaving just a bit of slack in the throttle cable.

With the engine off, twist the throttle to wide open throttle and let go of the throttle grip. The throttle should snap shut. If not, loosen the cables a bit or back the throttle grip a bit further off the handlebars. The throttle grip must work correctly or serious injury or death may result. This job must be done correctly. It's not difficult just make sure it's right.

Good luck
Steve

I FOUND IT IS STATED IN MANUAL FOR SONY A700 BATTERY GRIP.
REMOVE TRAY THAT HOLDS BATTERIES . REPLACE IN GRIP.
BUT THIS DID NOT WORK.
ONE BATTERY HAD NO CHARGE, THIS I FOUND CAUSED THE PROBLEM FOR ME. HAVE SINCE CHARGED BOTH BATTERIES AND PUT BACK IN GRIP,SEEMS TO HAVE SOLVED IT...... OR
USE JUST THE ONE BATTERY THAT WAS CHARGED.
THIS PROBLEM THAT I HAVE HAD IS NOT LISTED IN MANUAL.
BUT NOW THAT I KNOW OF IT I WILL KNOW HOW TO SORT IT
OUT .THIS MAY HELP SOMEBODY ELSE ONE DAY SHOULD IT HAPPEN.

THANKS ANYWAY

YOURS TRUELY,

HENRY NEILL

There is a button for the battery cover release on the bottom of the mouse. Slide the wireless usb adapter out and the button should be there.

The only thing I've run into with the grip is that my av dial doesn't work with the grip turned on. Its as if its taken over that function. I haven't checked the manual to see if this is normal.

i used to have the same problem with my Sanyo 2100mAh. i switched to the Uniross 2300mAh and problem solved. that was using my Ridata 512MB 40X solid state CF. switched to Hitachi 4GB MD (from Muvo2) and now the problem is back. i have learned to live with that though, as it causes no other problem for me except for the faulty battery indication.

Have you tried it with lithiums? It may not be a discharge problem so much as a low-battery detect problem. The NiMH are very low voltage even when fully charged compared with a lithium, maybe that's a clue. Either way it looks like a trip to Mr Pentax to get it orted :-( FWIW I use lithium AAs routinely, I tried some NiMH that I had and only got about 250 shots per charg and they failed a bit too abruptly - mid file write! - for my taste. I get 800-1200 shots from a set of Energizer AA lithiums, they give me plenty of warning of impending failure, I can stand the cost and I value the peace of mind that they give :-)

The cable connector on the *istD looks fairly flimsy to me and I am willing to bet it is not designed nor will it last as many insertion cycles as the CF card socket, also the CF card is much more tightly aligned less chance to damage contacts by inserting at an angle, near impossible. Any card reader is faster that using the cable, the cable is only USB1. You say you are lazy, but gee whiz you must be vey patient waiting for images to download via the cable at USB1 rates.