oil pressure and water temp gauges w/ V8


allpau2thou

10+ Year Member

Joined
Oct 21, 2011
Messages
247
Points
1,601
City
Haleiwa, Hi.
Vehicle Year
1991
Transmission
Automatic
I have a 1991 4.0L XLT ranger with a V8. Im installing a flip kit so I can use my new one piece driveshaft. Id like to take it for its first drive this week when its finished but I don't want to run it without water and oil gauges. Id like to use the stock gauges. Which wire goes to the oil pressure switch, and which wire goes to the water temp sensor? Thanks guys, A- :icon_cheers:
 
I believe that the oil pressure is white with a red stripe and water temp is red with a white stripe.

ps
They should be located on the driver's side rear/mid inner fender area in one of the wiring bundles there.
 
ok. I found those wires, they are in the same harness so that makes sense. How could I test them first?
 
I connected the red with white stripe to the water temp sensor in the manifold. Im not seeing any movement on the needle tho? I ran it for about 4 or 5 min and the needle didn't move. What did I do wrong?
 
If you just want to find which wire to use for oil psi and water temp like sparky said look and that bundle but what i would do is put your switch in the acc mode and you should be able to take the two wire colors he said and go to ground on the frame and you should see the gauge move. If the gauge doesnt move to your water temp or oil sending unit guess what you have the wrong wire..Those sending units are just looking for ground once you see them move inside your truck when grounding them just connect them to the correct sending unit and you are done.
 
Ok. Thanks. And can I look up the wire colors somewhere or do I just have to use trial and error?
 
i have a 91 myself with a 5.0 those wires are in that bundle on the driverside fender skirt..You just need to find the correct 2.Now some of them maybe hot if they are just touch them quick once you see a spark lol just remove the wire its only 12v it wont kill you it might just blow a fuse..Just like you say trail and error but once you find them you will know because your gauge inside the truck will move...
 
You were right about the oil pressure gauge wire... Driver side fender, white w/red. The water temp was black w light blue and it was in a harness on the passenger side. Thanks for the help. Now I just need to get a tach from a V8 Bronco/F150. Any idea what year Bronco/F150 has the same instrument cluster as the 91' 4.0L Ranger XLT?
 
lol yeah you are right about the water temp wire it ran in that bundle that was close by the battery tray...i found that silly as in how they ran that temp wire on the opposite side of the motor.on the tach i using my v6 tach it works pretty gud.
 

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