difference between 88 & 95 xj sending units

What the difference is for the 88 and 95 sending is? I plugged the 88 one into the 95 wires and my gas light turns on as soon as I plugged the battery in. The gas moves a little I don't have that much gas in it, but I don't hear the pump kick in either.
Thanks alot for all the help,
DR

Mechanically I can't tell you how they are different, but in 1991 Chrysler revised all the wiring. One of the differences is that the polarity of the gauges was reversed, and the ohm range for the senders is slightly different. Bottom line is, they are not interchangeable.

Thanks for the help.
DR

is there any write up on how to remove the gas tank. On the 95 I took my big crow bar and pounded it through the cargo area right over the rubber hoses and open the floor up to get it the hoses. I do not want to do this my 88 because I believe my cargo area is pretty solid unlike the 95( every floor board is rotted out including part of the cargo area not where I needed it though).
Thanks for all the help,
DR

What are you trying to do, remove the tank or replace the sender? The sender and fuel pump are accessible from under the vehicle (theoretically) without removing the tank. If you want to drop the tank, siphone out as much gas as possible, then find the two 'J' bolts at the forward ends of the two straps. Prop the tank in place with a floor jack (put a length of 2x6 or 2x8 on top of the jack so you don't punch through the tank. Remove the shiled under the fill neck and unclamp the hoses. Then remove the nuts from the 'J' bolts, remove the straps, and drop the tank. The hoses have to be coaxed through the opening in the frame, and it's a lot easier to deal with if the tank is empty.

The fuel pump is held into the tank by a lock ring, as you've probably already discovered.

the tank is pretty much empty. I am trying to remove the 95 tank and see what the condition of it to keep it or not to keep it. I couldn't really get a good swing to hit the brass punch to take the sending unit out. I also don't know what the top of the 88 tank looks like. I don't think it leaks gas but I really don't fill it more the $10-15 so I don't know for sure.
Thanks for all the help,
DR