key on power help

[TylerZ281500]

my test light died so i cant figure out which stud on the firewall junction block is key on power, im trying to hook up my electric fans

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[TylerZ281500]

anyone?

 

[jcoatswo]

I looked up a 1994 on alldata, not sure what year your truck is.

 

[TylerZ281500]

its a 93 not to be a bother but are their larger ones? i cant even zoom in on those without everything getting blurry

 

[jcoatswo]

Yea, I'm a newer member, how do I post large pictures rather than these little thumbnails?

 

[jcoatswo]

I'm looking at the diagram for the 93. Its looking like all 5 posts have power all the time. From what I'm reading it is literally just a solid block.

 

[TylerZ281500]

upload to photobucket and direct link it. so none of those would be key on power it seems, hmm can i just splice into the ignition power wire on my fuse block then?

 

[jcoatswo]

http://s1311.beta.photobucket.com/user/gmpartscheap/media/41870079_zps6d845070.gif.html?sort=3&o=1


http://s1311.beta.photobucket.com/user/gmpartscheap/media/41870080_zpsee5f86e2.gif.html?sort=3&o=0


http://s1311.beta.photobucket.com/user/gmpartscheap/media/41869787_zpsd177e8d9.gif.html

These are three photos from the 1993 model year (previous two were from 1994).

Looking at the bottom photo, the two connectors you can splice into on the steering column are labeled C255 and C256. Per the 2nd pic the pins you are able to use are as follows,

C255:

Pin 3- hot in Run and Start (probably not a good power source for an electric fan setup since you don't want the fans to draw power during cranking)

Pin 4- **which would be my personal choice** hot in ACC and Run (a good power source if you plan to use the aftermarket radiator temp sensor switch thing from autozone, the good thing about this pin and why it would be my choice is if you were to start overheating for any reason you could turn the engine off and put the ignition in ACC mode and the fan or fans would keep running)


C256:

Pin 300- hot in Run (still a good choice but pin 4 on C255 has the added ACC feature)

Personally I would run a wire from pin 4 on C255 to somewhere near the power distribution block and mount a relay on the firewall in or near the black plastic cover. Use your new wire to power up the relay and run a new (bigger gauge) wire off one of the 5 available pins in the power block to provide the actual high voltage power the fans require.

 

[TylerZ281500]

im liking c255 as well, cant figure out from that diagram which wire color i should splice into.

 

[jcoatswo]

1993 is too old for alldata to provide that info, their repair manual is pretty ty from about 1995 down when compared to newer vehicles. You can use the 2nd pic to see the shape of the connector then match pin 4 in reference to the shape/position of the connector if that makes sense.

If you can disconnect the connector and look at it straight on you can determine that pin 4 is the bottom right pin and go from there.