IAT sensor

[jdurham]

Looks like my grid heater doesn't work because the Intake Air Temperature (IAT) sensor is bad. Do any of you know the part number for the sensor? Mine is a 1990 non-intercooled 2wd.



Oh, many thanks to Philip for guiding me through the troubleshooting of this circuit. Your top notch!



Thanks,



Jim

 

[jdurham]

Well, since I didn't get any response on this, i contacted Cummins. They said they didn't have the sensor listed, and that it must be a Dodge part. I contacted the stealer, ordered the part, and it came in today. The MOPAR part number is 04429547 and cost $61. 26 Chrysler employee price), but the box is a Cummins box. After some very careful Chrysler label removal, the Cummins part number appears to be 2613547. I have neither verified this number, nor priced the part through Cummins now that I have a number, but I thought everyone might like to know, as it may save you some money if you have to replace it...



Jim

 

[BushWakr - RIP]

Hey Jim,



Glad you got that thing going. When/if you confirm the part number maybe you could go into the "Support for Parts" forum and add your part, description, and part number(s).



Bob.

 

[jdurham]

OK guys,



In case you haven't had any real experience with why the experienced guys call it the stealer and try to get things directly from Cummins, here is the reason:



I verified the part number is a good Cummins number for the Intake Air Temp sensor (3613547). This part was not listed by Cummins by the year and model of my truck, but when I got the number, they looked it right up.



Here's the catch, the stealer wanted 80 some odd dollars for it, and I got it for $61. 26 as a Chrysler employee discount. Cummins price for an individual was $36. 60:--)



As you can see, I could've gotten 2 of 'em for that, but I already installed it, and when I turned the key on, the relays made a loud clank, and the wait to start light came on, for the first time since 1990. Anyway, hope this helps someone else!



Jim

 

[BertM]

Jim,

Sounds like we are both having issues with the IAT sensor. Please see my post on WTS light constantly flashing. Where is the IAT located on these early engines? How do you check it? Thanks for the info on the part, it may be what I need.

 

[Dman]

Temp sensor price

This sensor (3613547) is listed on reliablegoods.com at $26. 64.

I use this website to check prices on cummins stuff. No connection to me. For future use - I have a cummins parts book for the 89 - 91. 5 engine. Give a yell and I'll look it up.



Dave

 

[jdurham]

Philip, let me know if I screw this up...



BertM



The IAT sensor is located on the driver's side of the engine. There is a solid looking bracket over the intake with a round hole in it. In that hole is the sensor, with 2 wires coming out of it. You can then check the resistance of the sensor at the given outdoor temp. One of the other guys with a manual will have to jump in here and give you the values, as I got mine from Philip. If the sensor is out of spec, replace it with the Cummins part number I listed (assuming it is the same as a 90 model). If the sensor shows to be in spec, then try the following:

There are 2 relays on the driver's fender well, and they look like they each have 2 larger (like a spark plug wire) wires connected to the top of them. The inboard side of each relay should read 12V all the time, while the outboard should read zero with the key off. To test the relays, disconnect the small wires from the side of the relay and jump a + wire to one lead and a - wire to the lead you connected the blue wire from. The relay should click and read 12V on the outboard lug with the large wire on it. If not, you have a bad relay. To perform a quick check of the system except for the sensor, unplug the sensor on the manifold, then turn on the key. The relays should click loudly, and the wait to start light should come on and flash slowly. Check the heater lugs (the other end of the spark plug looking wires on the intake), they each should read 12Vs. If so, it's probably the sensor. You'll have to turn off the switch, plug in the sensor, and turn the key back on to get the light to stop flashing. I hope you're not as confused reading this as I am writing it If you need to, pm me and I'll try to walk you through it, although there are a BUNCH of guys on here more knoledgable than I am...



Jim

 

[BertM]

Jim, Found the solid braket over the intake, found the hole(approx. 1 1/2"), found approx. 3/4" pipe plug in hole!? plug has the Cummins black paint all over it, does not look like it has ever been installed/removed. This is a very early '89 (9/88). Could there be another sensor location for this engine?

 

[jdurham]

I don't know, but I would figure that is where it would have to be. Mine is a 90 that is non intercooled, built in 89, so I figure they'd be the same. I'll go out to my truck and take a photo. Be back in a few...

 

[jdurham]

OK BertM,



Here is the photo. As you can see, the sensor is below the dipstick tube. It has a 2 wire connector plugged into it. Also, you can see the heater wires on the upper right side of the photo, on top of the intake with bleck rubber caps over them. Let me know how yours looks compared to this.



Jim

 

[BertM]

Jim, Exactly the same except no sensor in manifold, just a pipe plug. No empty plug from the wiring harness. Has got to located somewhere!? Could it be using coolant temp reading for WTS? I have a sensor in the back of the head on the driver's side and a sensor in the side of the block on the driver's side.

 

[jdurham]

BertM,



I am DEFINITELY no expert at this, but it seems they would have to be using air temp in the intake to be able to tell when the grid is needed. I will go back out and see if I have the same 2 sensors.



Jim

 

[jdurham]

I have the two sensors that you may be talking about. One is on the back side of the head and is a one wire sensor, the other being dirctly under the throttle linkage? If they are the same, maybe you should check your wiring harness to see if you have a connector that isn't being used or some cut wires. Let me know...



Jim

 

[BertM]

Jim, No cut wires, no unused connectors at the harness. Disconnected battery to reset computer. Tried unplugging the sensor on the side of the block, then turn ignition switch to the run position. No WTS light at all, only ABS and brake warnings lit up. Did the same with the temp sensor on block plugged back in. Garage is warm. Someone, somewhere knows how this curcuit works.