Anyone know where it is located? 1988 Dakota 3.9. Thanks.

 

on the intake manifold to the passenger side of the thermostat, right near the nipple for the heater hose

 

To amplify, on a 1988 TBI motor, the one to the PASSENGER side (under the A/C compressor) is the GAUGE sending unit.

The one to the DRIVER'S side is the ECT sensor; again, on a 1988.

Edit: Huh. I answered this earlier, don't know where it went. There is no air inlet charge temperature (ACT) sensor on a 1988; the ECU's engine coolant temperature sensor is to the driver's side of the thermostat housing with a 2-wire connector; the gauge's sending unit is to the PASSENGER side, under the A/C compressor location (or the A/C delete bracket), with a ONE wire connector.

RwP

 

Thx for your reply Ralph -- I concluded last night (after searching fruitlessly for the IMTS) one does not exist on my engine; so it's good to seed that confirmed in your reply.

I pulled the ECTS however... and it's resistance measures pretty close to the brand new one I just bought when placed in boiling water. So the question is... replace or do not replace? (it is the original ECTS). I say replace since I already have it out and they commonly fail above 150K miles. Thx. Oh, and one last question Ralph -- how often would you say the MAP sensors fail and need replacing on these engines? Which method do you prefer for testing the MAP sensor? Thanks again for all your help on wide variety of posts -- you are definitely the resident expert par excellence here.

 

I replaced mine when the ECU decided it had failed I dunno how to test it offhand, but there's a test in the FSM.

I'd go ahead and replace the ECT.

(BTW - my reman'ed TBI unit has the IAT sensor; but it's not connected. Came with the unit, so ... )

RwP

 

is that the one that's 1/2 plastic and 1/2 copper? If so, I'm surprised that after 30 years it didn't just crumble when you unhooked it or if not then when you took it out.... I know that 88 is pre Magnum but its been too long since I messed with one of those...
I know that the ones on the Magnums do after a few years and those aren't 30 years old, yet. For what they cost, (not much) put the new one in.