Hi

Its sounding like a broken wire to me & ive seen plenty of broken side shift loom wires over the years ha ha

Lift the forks up to working height & reach fully out then turn the truck off & disconeect the battery, take the inspection covers off & then stand in the reach carriage facing the forks.

There should be a white 3 pin connection on the back of the fork carriage to the left hand side, it can be well hidden, this is for the side shift valve block.

A RR B3 will be the 1.6 ton mast so that has the side shift loom come down the side of the mast.

In the reach carriage area in the left hand corner where the all the connections are, it should be top row 2nd in from the left for the side shift loom.

You need these 3 wire to work the sideshift valve block, normally there are a couple of spare wires in the loom.

Id look for short circuits & continuity in these 3 wires, there are little white number tags at each end to id them.

The tilting when the loom is disconnected & the sideshift joystick is operated is totally normal.

The current reach loom BT will supply does have extra plugs on that are for optional equipment, its easier for them to just make / stock one loom.

There are mod kits of new rollers to help stop the loom breaking, they are **** expensive, RS components do a roll of 4 core cable that is suitable to make your own new sideshift loom from.

Ill get the part number & price for the protection loom, it has 2 x 3 amp fuses in that will blow if the sideshift loom shorts itself out to save the A5 card from being damaged, there is also a service bulliten about the protection loom ill send you later

Ill be back on here later this evening.