I don't know how common people have changed these, but I just changed mine and it will not take that long providing you have the right tools. My car has 116k on the clock and it finally went out; anyone else's go out around this time? So anyway, it's about $28 for the unit depending on where you go and the one you will get is SMALLER than the one from the factory. I am pretty sure the units on my 91 were just above the oil filter from 88-92 and is in somewhat an inconvinent place because the firewall sticks out so you cannot get a deep socket on it. The old is an all metal casing and about 1/4" longer while the new one has a plastic casing. I have included some pics of the new one, location, and the tools needed. The tools shown are a little pipe wrench which really helps to put the new one on and the other is like a crows foot that is 1 3/16". The nut thing on the old one is that 1 3/16" size, but the new one is 1 1/16" so you will need two sockets. These were Snap-ons so you can hunt down the truck, go to sears, or try a swap meet. Hope this helps anyone who will be replaing one anytime soon.

The location and you can see where the firewall sticks out

The new unit

The 1 3/16" crows foot 1/2" drive and pipe wrench