can anyone figure this out?

[fordtrucks4toys]

1992 explorer , 2 door. 4.0L . revers lights dont come on, turn signals do not work, when you turn the key to one , the needle on the RPM gauge stays at 4 , constantly when it is on. the wipers will some times turn on and wont shut off,even though its off, itll just move across the windshield.some days it will work fine.any one have any ideas?

i replaced the turnsignal flasher,all fuses are good,bulbs are good.
could it be the switch? my main thing is turn signals, when you engage the turn signal switch you can here a click like normal.hope it would be the whole assymbly. is there any way of testing it? also do you got to remove the steering wheel to get hte switch off? theres 2 small bolts that i can get to and then it looks like there may be 2 torx screws going holing it in.

help please!!

 

[olranger]

that sounds like the turn signal switch, you know how the turn and window wipers are all in one, probably wore out and shorting through the system making it do weird things, the tach i dont know, bad tach possibly.