I have a 88 bronco 2 with the 2.9 with auto. I am looking into hooking up an aftermarket temp. gauge. I'm not really sure on how to hook it up and was wondering if anyone has done it before. The stocker still works but fluctuates alot so its not really reliable. Plus i like the look of aftermarket ones. I cant really find anything on this procedure so can some one please help!!
The aftermarket gauge will probably have the sending unit to install, and a lot of them come with the correct brass fitting to fasten the sending unit in (or it may bolt in OK as-is, you'll just have to see). Either way, you can probably find the fitting you will need. I have done this only on my 5.0L, so the fitting and what the sending unit size is, is the unknown for me. Use a small amount of teflon tape on the treads to make sure they don't leak. The sending unit still needs to touch ground (or make some contact with the threads in the lower intake).
There's a hole in the fire wall on the driver's side that you can route the wire through, but put a grommet in the wire wall so that the fire wall does not gradually eat through the wire over time and ground out.
On my '88, the fuse for the power locks or windows (can't remember which), was hot, but didn't run to anything (and also no fuse). Autoparts stores carry fuse holders that plug into existing fuses locations with an additional wire that will allow you to add the power to the gauge from the fuse box. Solder and shrink wrap (or crimp if that's all you got) the postitve there.
Ground can go to anywhere metal on the chasis..