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Waterloo

Just thought I would post this information regarding our ProStar HVAC systems and the TWO potential FIRE hazards in your dash. I have a 2008 model, built in 2007. Sadly, few of the dealers know about these TSBs, you have to know what to ask, and have a service manager that will take the time to look. The TSBs are there, we found them under wiring, or electrical harness. My particular truck was not covered by these TSBs, but I sure had the problems! So, even if you do not fall under these two TSBs, just do these fixes, it may just save your life, your ride and your income.

On Edit: If you don't want to read the entire post, skip directly to the last paragraph.

One TSB relates to the HVAC blower motor wiring harness, the other is for the Linear Power Module mounted on the blower motor. This is your cab blower motor for the front HVAC, not the sleeper HVAC system.

The issue, the blower motor draws quite a bit of amperage. The old fix was to pull the 30 amp breaker and replace with a standard automotive 30 amp fuse. The breaker would overheat and fail due to the high amp draw and heat. When this happens your blower motor will not work until everything cools down, or you reset your breaker.

The automotive fuses suffer the same overheat fate but are cheaper than breakers, they normally have to be replaced several times a year in my truck as they do fail. And they fail without blowing. The dealers fix is to install a new blower motor. The blower will work until the fuse or breaker heats back up... Sweet little racket the dealers have going...

In time, these fuses will eventually melt and a breaker will just fail. The fuse block will also melt, due to the high amps/heat, as will your wiring connections/harness. My fuse block is melted where this fuse/breaker sits as were my harness connectors. This is the fire hazard and the reason the TSB was issued. Problem is, it took several calls to the dealer before I got my guy to dig for it, and he found it, as again, my truck does not fall under this TSB. I do not have the TSB number, but I have the fix.

International has a jumper, or as it says on my receipt, Cable ASM -HVAC Jumper W/Resistor. The part number is 3865234C92. There is a resistor soldered in line on the power side, it sucks up the heat/amp draw that causes everything to melt, and or the potential to catch FIRE.

The cost for this jumper/resistor at my dealer was $34.83, list is $46.44. You can also find this part on the internet for a bit less. Myself, I would just purchase this at the dealer, that way you know you are getting the correct part. Just my .02

You will need to pull the lower kick panel, locate the harness that runs along the floorboard at the firewall. I do not recall if you had to pull the HVAC box apart to get to the blower motor LPM connector. I don't think you do. This cable plugs in between the HVAC harness and the blower motor LPM harness. If your connections are melted, like mine were, clean up as best you can. I used a small pick and screwdriver to square it all away. It was almost to the point of not being usable, I got lucky, the plug was a mess but fixable. To add, the dealer does not sell replacement plug pigtails, you are on your own there.

This new harness w/resistor is suppose to solve the overheating issue and eliminates the potential fire hazard. FIRE hazard, did you hear that? FIRE. Purchase and install this part ASAP even if you are not on the TSB list. Remember, my truck was not on the list either but was affected. I would say that the older your wiring gets, the greater potential for fire. Don't mess around, just do this. So far, I have had no issues with my blower motor or HVAC system since doing this fix, it seems to have solved the problem. And I was eating blower motors, I have installed three this year alone, replaced under warranty... This third blower motor is working as it should since the harness fix was installed, I am now confident this solved my problems. .

The other FIRE hazard in your dash is the Linear Power Module. That is found attached to your HVAC blower motor. You will need to remove the kick panel and front lower cover to get to the air box that holds the blower motor and LPM. It is held in with half a dozen torx head screws. There are two at the floorboard. There are also two, one on each side of the air box that you have to dig for to get to. They are located at 9 and 3 o'clock on either side of the blower/air box. The rest of the screws are at the top and visible, I believe there are three more, just below the fuse block.

Anyway, dig the blower motor out, the Linear Power Module is the White, 1/4 circle thing with the spikes on it. It is held in place with two torx head screws. The part number is 3562102-C1 and has a TSB for potential fire hazard, it overheats just as the blower motor harness does and is a potential FIRE HAZARD according to Navistar.

So, I bought a new one at the dealer, FIRE, I ain't screwing around. It was roughly $250 and I ate it. Meanwhile, just a few months prior, I had bought a Linear Power Module from these guys for $65. http://www.truckerac.com/blower-resistor...21021.html

It is the identical part that I purchased at the dealer. Same barcode, same numbers, same manufacturer, same stampings, same everything. I could not tell the difference between the two so I left it in and will keep the $250 one as a spare. I also called Trucker AC to find out the date of manufacture, he told me the one I had just purchased a month or two ago were just delivered direct from the manufacturer, they were the latest OEM model. I was confident with the answer as these parts were visually identical, but had different stampings than an older LPM I had laying around. So I think I am OK, but that is up to you which part you purchase.

There you have it folks! I hope this helps someone, and I would do these repairs ASAP, especially if you are having blower motor issues. Check your fuse block under the cover of your dash. The fuse is right up front center. If you see charing on the block, you are playing with FIRE. Also, if you have to periodically reset that HVAC Blower Breaker going down the road, you have this problem. Or, if you run the blower motor on high and it starts acting up, you have this problem, FIX IT, purchase that Jumper Cable. If your truck catches fire it will go up in flames in seconds. I have seen a few burn to the ground, and when they go, they go. By time you get to your fire extinguisher it will be to late.

Rawze

I am going to have to look at my own truck now. lol

Thank you for taking the time to explain so well. It is cool to see a detailed explanation that helps others.

Brock

Good info! I can't turn my blower over halfway or it overheats and shuts down. I've replaced the blower motor and blower motor resistor but still don't fix it, it doesn't seem to be blowing as well as it should so I've come to the conclusion that maybe my blend door is jammed or I have something blocking my plumbing. While I'm in there, I will definitely upgrade the harness!

Waterloo

Brock, that is the same problem I had with mine, same symptons, I thought blend door was stuck too, I even replaced the actuator! But nope, it was the harness overheating. I bet when you unplug the main HVAC harness from your blower motor you will find some signs of overheating. The new jumper/resistor should cure your problems, it has mine.

Waterloo

Here is the TSB... My particular ProStar was built in 2007, a 2008 model... Notice it does not fall under the TSB... According to this, that harness is free of charge if you fall under these dates.

Campaign:14V688000 on 10/30/2014

Component: Electrical system

Manufactured: 12/15/2008 - 06/19/2014

Affected: 18,798

Defect: Navistar, inc. (navistar) is recalling certain model year 2010-2015 international lonestar vehicles manufactured october 12, 2009, to june 16, 2014, and 2009-2015 international prostar vehicles manufactured december 16, 2008, to june 20, 2014. in the affected vehicles the electrical harness that supplies power to the hvac system may not be of sufficient size for the electrical load of the circuit. this can result in an increase in resistance and heating at the connectors.

Consequence: An increase in resistance and heating at the connectors could cause a vehicle fire.

Correction: Navistar will notify owners, and dealers will replace the 60 amp relay and battery harness with a 150 amp relay and battery harness, free of charge. navistar issued an interim notification to owners on december 29, 2014. the recall began on march 2, 2015. owners may contact navistar customer service at 1-331-332-1590. navistar's number for this recall is 14516.

Notes: Owners may also contact the national highway traffic safety administration vehicle safety hotline at 1-888-327-4236 (tty 1-800-424-9153), or go to http://www.safercar.gov.

74bassman

my prostar justed started doing this last week. The truck is 2010 model built in 09. I did reolace the blower motor already, but i will have to look into this harness. My truck is now leaking coolant out of the vent where the condensation comes out when you run the AC. I replaced the heater core but it is still doing it. I also do not have heat when going down the road, just blows cold air. When i stop the heat works then. could this be the harness or a blend door actuator going out?

Waterloo

(12-01-2017 )74bassman Wrote: my prostar justed started doing this last week. The truck is 2010 model built in 09. I did reolace the blower motor already, but i will have to look into this harness. My truck is now leaking coolant out of the vent where the condensation comes out when you run the AC. I replaced the heater core but it is still doing it. I also do not have heat when going down the road, just blows cold air. When i stop the heat works then. could this be the harness or a blend door actuator going out?

Well, coolant out of the box... Sounds like you are going back in... Something is lose or the new core is bad.

Up under the hood is another blend door actuator, it is located on the side of the fresh air filter box. They rarely fail, but there is one there. You will have to remove the windshield wiper cowl to get to it up at the firewall... Also, it is a different part number than the two inside the cab in your dash.

I would also head to your local International dealer and get this harness 3865234C92 if you have not yet.

If the blower motor is not running, I would remove and bench test it to rule out a wiring issue. I thought mine was bad until I bench tested it, it was not the blower, it worked. The above harness should solve most blower motor issues. See my warning below... It does not fix everything.

Check the blend door actuators to make sure they are working. You should hear the blend doors opening and closing. If not, more than likely a bad actuator. I would also check to see if they are getting power from the HVAC control unit to the actuators. I have had to replace mine twice already, the HVAC control unit, it was not sending the signal to the top blend door actuator.

Here are the wiring schematics to your truck... http://bodybuilder.navistar.com/General/...s08339.pdf

Also, check all of the wiring going to the HVAC control, I found a broken wire up under the dash and repaired. No clue how that happened, but it did... No relation to the blend door issues I was having. Inspect ALL wiring.

In the fuse block up top, check the 30 amp blower motor fuse, it is front center as you are looking at the block. They tend to overheat and melt the plastic block. I would keep 30 amp fuses on hand, they tend to fail. They will test good, but are not, the same can be said for the other fuses. I tend to replace mine annually. It sucks, but normally solves other issues.

One other thing, "THE WARNING", at least on my ProStar, do not run the blower motor on the highest setting, you can go to the position just before it, but not full blast. If I run mine on high, all the way up, the motor overheats and quits working. Only way I have found to fix is to remove the blower motor and unplug it, then plug it back in along with the Linear Power Modulator. A real PIA. this resets and everything then works.

And last but not least, find your Ambient Air Temperature Sensor and get it out in the open... I dug mine out from under the radiator and hooked up to the windshield wiper cowl where the hood and driver door meet. Here is a photo...

Moving that sensor solved all of my AC issues, and there were many, thousands of dollars worth.

I hope this helps... Those wiring schematics will be your new friend. ;-)

74bassman

The 30 amp fuse gets so hot it burns my fingers. I did go to Rush here in Atl, and they want me to bring the truck in to replace that harness. They said it would take about 1 week for them to get to it. So, I'm just going to buy the harness and do it my self. Does this harness plug directly into the plugs that are there? I figure I was going to have to go back into heater core, and blower motor area. I did take out the passenger seat and left it out to run this week to test the fixes. good thing thing i haven't put it all back together.

When i find and move the ambient air temperature sensor will i have to add any wire to it.

Waterloo

(12-01-2017 )74bassman Wrote: The 30 amp fuse gets so hot it burns my fingers. I did go to Rush here in Atl, and they want me to bring the truck in to replace that harness. They said it would take about 1 week for them to get to it. So, I'm just going to buy the harness and do it my self. Does this harness plug directly into the plugs that are there? I figure I was going to have to go back into heater core, and blower motor area. I did take out the passenger seat and left it out to run this week to test the fixes. good thing thing i haven't put it all back together.

When i find and move the ambient air temperature sensor will i have to add any wire to it.

One hour job at most to install the plug, and yes, it is plug and play. You just need a torx bit and ratchet, easy peasy...