For this 83 D-150 , working through the planning process of installing an electric radiator fan and at the same time upgrading the engine bay wiring to have relays for an electric fuel pump, HEI and ....

the power control module / fan from a mid 90 Caravan seemed to be a proven starting point.
For the fan temp sensor, considered the bulbs that attach to the exterior of the radiator, but wanted the fan to react to engine water temp directly.
Found this extensive listing of temp sensors
http://www.wellsmfgcorp.com/ds_fans.php ... mit=Submit


these folks will sell single switch through www.scautoonline.com at decent prices. Decided I wanted the ability to select the fan on temp.
Found an Adjustable Universal Temperature switch at www.autospeed.com
Ended up going with a Devale 16749 Adjustable fan controller through Summit
http://www.summitracing.com/search/?key ... 6749&dds=1


I wanted to incorporate the high - low speed fan speed feature as well as have the radiator fan react to the the AC compressor energizing (the truck does not now have AC, adding AC is also part of the plan).

Sketched out how I believed the wiring should be and made up a test bench with a battery, rad fan, relay box, Devale controller, ac compressor, six button interior AC / heat control unit.. to test it out.

It works,, fan activates with the engine temp switch, and / or when the AC is selected with the six button controller. I elected to also be able to switch on the fan with a separate dash switch. When the dash switch is on, and the AC or engine switch also energize, the radiator fan is in a super duty cycle, really moves some air.
the wiring set up is shown here
http://www.flickr.com/photos/13718356@N ... 009363186/


this is part of the overall plan to relocate the battery to the bed of the truck, The basic plan should be applicable to other vehicles
have a few other system changes to plan out, including upgrading the gauge cluster, then will get this project implemented.

thanks
Dadtruck