Engine/Transmission (1998.5 - 2002) Ambient Air Sensor

[kboettcher]

Does anyone know what the "Ambient air sensor" resistance readings should be?

I believe this is the sensor that is under the drivers battery, correct? Is this not the sensor that the grid heaters use to determine if and how long they should be on? For some reason my grid heaters dont seem to be coming on unless it is very cold out.

 

[JCyrbok]

Sensor

I thought that the Grid Heaters used the Intake Air Temp sensor in the intake manifold to determine run time. Not 100% sure though.



J-

 

[kboettcher]

I think they use the IAT sensor after the vehicle is running , but at startup I believe it uses the ambient air sensor. hopefully I will be able to answer some of these questions myself once the manuals arrive, I ordered the servive manuals, but they said allow 14 days for delivery . but only 7 more sleeps and they should be here.

 

[illflem]

The IAT controls the grids. The service manual gives resistance values at several different temperatures. I'd give them to you but only have 12 valve manuals, don't want to supply misinformation.

 

[davemac]

This should give you the #`s you`re looking for.



http://www.dodgeram.org/tech/dsl/sensors/IAT/clean.htm

 

[kboettcher]

davemac



Those are the readings for the "IAT sensor". I'm looking for the readings for the "Ambient Air sensor" which is the one under the driverside battery. Thanks for trying but I already seen those and have changed that sensor last week.

 

[illflem]

The Battery Temperature Sender (BTS), under the battery is used to vary the charging rate from the alternator according to the battery temp. It has nothing to do with the grid heaters.



The Ambient air sensor is the sensor for the thermometer on the overhead console, also nothing to do with the grids.



Most grid heater problems can be traced to loose connections at the heater relays or bad relays.

 

[kboettcher]

hmmmmmmmmm



Ok, well the parts idiot at the dodge dealer said that was the ambient air sensor, and just thought I would check it out to see if it was in range. I already found my relay problem, they were cooked. Loose cables. I am in the prossess of getting new solenoids for my heaters from an HVAC parts supplier (no relation to the one who posts here ) the dodge dealer wanted $90 for the pair and I am getting the sameones delivered to my door for $17 each, then I will just bend back the tabs on the old bracket, remove the old ones and put the new ones right in the same place. They are made by the same company and will fit right in. Only problem is they are 3 weeks delivery, had to come from the factory. But looks like I have been without them since I bought the truck a month ago anyway. Small price to pay for the savings, I'll just keep it plugged in if it gets cold.

 

[99guy]

Originally posted by kboettcher

hmmmmmmmmm



I am in the prossess of getting new solenoids for my heaters from an HVAC parts supplier (no relation to the one who posts here ) the dodge dealer wanted $90 for the pair and I am getting the sameones delivered to my door for $17 each

I do some hvac work too. Haven't checked my supplier yet, just curious if you knew more specifics on what relay to look for???

 

[kboettcher]

The relay is made by White-Rogers, and the part number I asked for was the "120-105111-1". It a 12V DC Coil with continuos duty rating. My supplier said that part had been replaced by "120-901"



Here is the White-Rodgers original spec sheet, and this is the spec my supplier gave me. I hope this helps you.

 

[99guy]

Originally posted by kboettcher

The relay is made by White-Rogers, and the part number I asked for was ...

Thanks a bunch , I think you just saved me some $$. Found a bad relay in my 99 last night.

 

[kboettcher]

Finally got my new grid heater solenoids from the hvac supplier. They don't quite fit the oem bracket so I just fabbed some new ones from some 18ga. sheet metal. They seem to be working good now, but only time will tell how long these ones last. They look just as heavy duty if not a little more than the oem ones. Will keep you informed how they work and let you all know if they don't last.

 

[kscheffler]

I recently check my abient air sensor with a calibrated thermometer and it is reading high by 3 degrees F. Dodge says that it is only 2 degrees off and is within the specifications for the sensor. Has anyone ran accross the specificaitions for the ambient air sensor; I would like to prove them wrong. 2 or 3 degrees is a big deal when you get close to 32... .