floridawheels
Active Expediter
(PART 1)
A/C Heater blower motor and A/C in general
First let me say THANK YOU Mr. Greasy for all the help you have given me!!
Now, about that blower motor and A/C....
2007 Hino 338 - I live/work in Florida and I do not like to be hot. I have had this truck going on 2 years now. First summer was rough, second summer, much better. I'll condense the story greatly.
I have a large sleeper (96") on my truck and of course it has an underbunk A/C unit tied into the factory dash system.
The air blowing from either the dash or the bunk unit was cool but I could never get it to be real cold. At one point the fan started blowing less and less. What follows below will bypass all the trials, tribulations and experiments to try to fix those issues and i'll get right to the bottom line of what was done to finally effectively fix everything.
The fan motor was replaced, air flow improved for about 2 months, then quit again. The cause was a melted switch AND plug. The fix was to replace both the switch and the plug. The part numbers for the plug are hard to find but it is available. I got it as a plug and had to order a pigtail wire for each of the contacts, (It comes with the contact and about 4" of wire). There are different colors and sizes. With enough searching your parts person can eventually find the correct part numbers.
Pull the dash trim off and remove the 3 screws holding the A/C control panel. You won't be able to pull the control panel out very far because of the control cables for the temperature valve and air doors but you can get it out enough. Pull the plug out of the back of the switch, if it looks melty, replace both the switch and plug. (You can of course replace just the switch but most likely you'll soon be replacing the switch again and this time the plug as well - Ask me how I know this... Sigh)
When you go to replace the plug do it correctly or your going to have problems later. When splicing wires I only ever either solder and marine grade heat shrink or use high quality (expensive) marine grade crimp terminals with heat shrink. (The marine grade heat shrink has glue inside it to give you a weatherproof connection). Either of these methods give you a high quality connection that will last over time and will not cause a heat issue. The marine grade heat shrink helps act as a strain relief for the connection by physically bonding to the wire preventing it from wanting to pull out of the connection. Use caution when heating the shrink tubing not to melt other things in the area. Cover them with something... Aluminum foil works well as a "Blast shield" over the things behind your connection. Also, Harbor Freight sells a decent heat gun for about $20 and they have an accessory kit for it that has a few different "tips" or nozzles. 1 of them has a "U" shaped end that partially captures the hot air and directs it to the back of your connection making it much easier to properly apply heat to all sides of your connection. That nozzle kit is about $10.
So now you have a new switch and plug but your still not getting the proper air flow... Of course I should mention the AIR FILTER... It is located under the dash right where your passenger left foot is. I clean mine WEEKLY, more often in the summer because it gets dirty faster in the summer. All you have to do it grab the tab and pull it out. It sort of "hinges" in the back so the front comes out first (Front as in front of the truck). Take it outside, pay attention to the wind and just tap it on something hard, like the bumper, step, whatever. All the crap will fall off. It looks cheap and flimsy to me so I bought another one (About $20 if I remember correctly) to have just in case, (I am a firm believer in having spare parts available (When possible/practical) when you need them, not having to wait weeks for Hino to get around to shipping/delivering them). So far I have not had to use it.
The fan - Replacing the fan can look like it will be a real pain in the butt. It sort of is but it is also not that bad. The first time I installed a new fan, (yes, the first new fan...) I did just the fan. Pull off the panel over the fuses and the lower center dash panel just to the left of that. There are a couple screws in the center panel, make sure you remove them before you just try to snatch it out. I found the simplest way to remove the fan is to remove the top half of the fan housing assembly bring it and the attached fan out of the dash. Swap out the fan and reinstall everything in reverse order.
That said.... There is also a RESISTOR in the electric system for the fan. This resistor wears out and can/will cause you issues. I did not replace the resistor the first time. This last time I did, more on that later. The resistor is located pretty much on the firewall behind and to the left of the blower housing. Once you have the center trim off, assuming you know what your looking for, you can see the resistor. Seeing it is one thing, touching it.... well that's another story... LOL.. However, once you have the upper fan housing out, getting to the resistor is not all that hard. So, If... IF your going to replace the resistor, when you have the housing apart to replace the fan is an ideal time to do it.
So, this second time I replace the fan, (I use my A/C 6 days a week, pretty much 24 hours a day. The fan lasted about 1 year, roughly 7,500 hours of use - You would think it would last longer than that?!?) Anyway, The second fan replacement I also purchased the resistor (About $45). Once I removed the fan I plugged the new fan in and tested it. It did work, indicating that the resistor was still serviceable. I had the new resistor on hand in no small part because Mr. Greasy had told me to try the resistor first, (And the local parts people also told me that the resistor often goes out). Since I had a replacement resistor on hand and now had access to the old resistor I figured I might as well install the new one even though the old one seemed to be working. Everything was reassembled.
NOTE: Before replacing the fan for the second time I inspected the switch/plug. This time both looked to be in perfect condition but this of course might not always be the case so it is a real good idea to pull the dash apart enough to inspect those parts before just going straight to fan replacement.
With both the motor and resistor replaced the air flow from the dash vents is AT LEAST 25% more now than it has ever been since I bought the truck. Next year when the fan goes out again, I'll be spending the extra $45 for another new resistor as well.
Now about the temperature of the air coming from the vents. I'll not go into the entire theory of how the A/C system goes about making the air cold but I will tell you it is a pretty particular system and things have to be functioning just right to get optimum results (The coldest air possible).
I went to a local A/C shop and they said they thought that even though the pressures seemed to be in the acceptable range that probably my compressor was weak. Also, with the system that was as old as mine (remember, truck is a 2007) the condenser (The radiator looking thing on the front of the truck) might be an issue.
I spoke to Mr. Greasy about all of this and he recommended that I check the air flow through the condenser/radiator because the air passages often get clogged with bugs and other debris greatly reducing the ability of the air to pass through. Mr. Greasy also strongly advised against using a pressure washer on the condenser as it is not real strong and the pressure can easily damage it. After having removed mine and looked at it, I will strongly second that. In my particular case there was absolutely minimal crap blocking the air so what was there was removed and onto the next step.
Fan clutch - At highway speed the air was cool, almost cold. At idle is was barely cooler than outside air. This of course tells us that the air flow at idle is not sufficient. I could use the high idle know bit increase engine RPM which helped some. Opening the hood also helped if I was going to be somewhere for an extended period of time. But this was not really an acceptable solution. I felt strongly that the fan clutch was not functioning properly so I discussed this with Mr. Greasy. (And later Hino techs at 2 different dealerships that looked at it). There really is not a definitive way to easily tell if the clutch is working or not but I finally decided my sanity and comfort was worth the almost $500 for a new fan clutch so I bought and installed a new one. It did not seem to make any difference at all. Not only did the air not get any colder but it did not seem to make any difference in engine temp and knowing what it is supposed to sound like, I did not hear any difference either.
Roughly 6 months after installing the new fan clutch my turbo went out. I took it to a dealership (Not either of the 2 that had looked at my fan before). While the mechanic was changing out the turbo I mentioned the fan clutch. He gave it a spin and immediately said,"This clutch is no good". I had them install a new one and send the "Other new one" in for warranty claim, (That's another story buy I did eventually get a warranty refund on that). So it seems that the new one I had first installed was likely no good right from the start. With the second new one on the truck the temps did come down some and it does seem to sound more like expected.
Air still not really cold enough - OK, now we are going all in for cold air. New A/C compressor, new condenser, new dryer, new expansion valve. Careful and 100% complete flush of entire A/C system. (Note, the dryer on this system is inside the condenser. It is individually replaceable but when you get a new condenser it comes with a new dryer installed). More improvement but still not where I wanted to be.
More discussion with the A/C shop guy and a visit to 2 different Thermo King shops. The conclusion was that perhaps the stock compressor and or stock condenser was not fully up to the task of providing the needed pressure and system cooling to provide the needed "Stuff" for both the dash and underbunk systems. After much research and discussion it was determined that there was not a feasible replacement for the compressor but enhancements could be made to the condenser part of the system.
Now to help you understand some about this I'll give a simple and partial explanation of how part of the A/C system works. When the compressor does it's job of compressing the Freon gas the gas gets hot. This hot gas needs to be cooled down in order to do it's job of making the air cold. The condenser is the part that does the cooling of the hot Freon gas. It was reasoned by those I discussed this with that perhaps there was simply not enough condenser area for the gas to properly cool. Installing a larger condenser in the factory location was not practical.
A/C Heater blower motor and A/C in general
First let me say THANK YOU Mr. Greasy for all the help you have given me!!
Now, about that blower motor and A/C....
2007 Hino 338 - I live/work in Florida and I do not like to be hot. I have had this truck going on 2 years now. First summer was rough, second summer, much better. I'll condense the story greatly.
I have a large sleeper (96") on my truck and of course it has an underbunk A/C unit tied into the factory dash system.
The air blowing from either the dash or the bunk unit was cool but I could never get it to be real cold. At one point the fan started blowing less and less. What follows below will bypass all the trials, tribulations and experiments to try to fix those issues and i'll get right to the bottom line of what was done to finally effectively fix everything.
The fan motor was replaced, air flow improved for about 2 months, then quit again. The cause was a melted switch AND plug. The fix was to replace both the switch and the plug. The part numbers for the plug are hard to find but it is available. I got it as a plug and had to order a pigtail wire for each of the contacts, (It comes with the contact and about 4" of wire). There are different colors and sizes. With enough searching your parts person can eventually find the correct part numbers.
Pull the dash trim off and remove the 3 screws holding the A/C control panel. You won't be able to pull the control panel out very far because of the control cables for the temperature valve and air doors but you can get it out enough. Pull the plug out of the back of the switch, if it looks melty, replace both the switch and plug. (You can of course replace just the switch but most likely you'll soon be replacing the switch again and this time the plug as well - Ask me how I know this... Sigh)
When you go to replace the plug do it correctly or your going to have problems later. When splicing wires I only ever either solder and marine grade heat shrink or use high quality (expensive) marine grade crimp terminals with heat shrink. (The marine grade heat shrink has glue inside it to give you a weatherproof connection). Either of these methods give you a high quality connection that will last over time and will not cause a heat issue. The marine grade heat shrink helps act as a strain relief for the connection by physically bonding to the wire preventing it from wanting to pull out of the connection. Use caution when heating the shrink tubing not to melt other things in the area. Cover them with something... Aluminum foil works well as a "Blast shield" over the things behind your connection. Also, Harbor Freight sells a decent heat gun for about $20 and they have an accessory kit for it that has a few different "tips" or nozzles. 1 of them has a "U" shaped end that partially captures the hot air and directs it to the back of your connection making it much easier to properly apply heat to all sides of your connection. That nozzle kit is about $10.
So now you have a new switch and plug but your still not getting the proper air flow... Of course I should mention the AIR FILTER... It is located under the dash right where your passenger left foot is. I clean mine WEEKLY, more often in the summer because it gets dirty faster in the summer. All you have to do it grab the tab and pull it out. It sort of "hinges" in the back so the front comes out first (Front as in front of the truck). Take it outside, pay attention to the wind and just tap it on something hard, like the bumper, step, whatever. All the crap will fall off. It looks cheap and flimsy to me so I bought another one (About $20 if I remember correctly) to have just in case, (I am a firm believer in having spare parts available (When possible/practical) when you need them, not having to wait weeks for Hino to get around to shipping/delivering them). So far I have not had to use it.
The fan - Replacing the fan can look like it will be a real pain in the butt. It sort of is but it is also not that bad. The first time I installed a new fan, (yes, the first new fan...) I did just the fan. Pull off the panel over the fuses and the lower center dash panel just to the left of that. There are a couple screws in the center panel, make sure you remove them before you just try to snatch it out. I found the simplest way to remove the fan is to remove the top half of the fan housing assembly bring it and the attached fan out of the dash. Swap out the fan and reinstall everything in reverse order.
That said.... There is also a RESISTOR in the electric system for the fan. This resistor wears out and can/will cause you issues. I did not replace the resistor the first time. This last time I did, more on that later. The resistor is located pretty much on the firewall behind and to the left of the blower housing. Once you have the center trim off, assuming you know what your looking for, you can see the resistor. Seeing it is one thing, touching it.... well that's another story... LOL.. However, once you have the upper fan housing out, getting to the resistor is not all that hard. So, If... IF your going to replace the resistor, when you have the housing apart to replace the fan is an ideal time to do it.
So, this second time I replace the fan, (I use my A/C 6 days a week, pretty much 24 hours a day. The fan lasted about 1 year, roughly 7,500 hours of use - You would think it would last longer than that?!?) Anyway, The second fan replacement I also purchased the resistor (About $45). Once I removed the fan I plugged the new fan in and tested it. It did work, indicating that the resistor was still serviceable. I had the new resistor on hand in no small part because Mr. Greasy had told me to try the resistor first, (And the local parts people also told me that the resistor often goes out). Since I had a replacement resistor on hand and now had access to the old resistor I figured I might as well install the new one even though the old one seemed to be working. Everything was reassembled.
NOTE: Before replacing the fan for the second time I inspected the switch/plug. This time both looked to be in perfect condition but this of course might not always be the case so it is a real good idea to pull the dash apart enough to inspect those parts before just going straight to fan replacement.
With both the motor and resistor replaced the air flow from the dash vents is AT LEAST 25% more now than it has ever been since I bought the truck. Next year when the fan goes out again, I'll be spending the extra $45 for another new resistor as well.
Now about the temperature of the air coming from the vents. I'll not go into the entire theory of how the A/C system goes about making the air cold but I will tell you it is a pretty particular system and things have to be functioning just right to get optimum results (The coldest air possible).
I went to a local A/C shop and they said they thought that even though the pressures seemed to be in the acceptable range that probably my compressor was weak. Also, with the system that was as old as mine (remember, truck is a 2007) the condenser (The radiator looking thing on the front of the truck) might be an issue.
I spoke to Mr. Greasy about all of this and he recommended that I check the air flow through the condenser/radiator because the air passages often get clogged with bugs and other debris greatly reducing the ability of the air to pass through. Mr. Greasy also strongly advised against using a pressure washer on the condenser as it is not real strong and the pressure can easily damage it. After having removed mine and looked at it, I will strongly second that. In my particular case there was absolutely minimal crap blocking the air so what was there was removed and onto the next step.
Fan clutch - At highway speed the air was cool, almost cold. At idle is was barely cooler than outside air. This of course tells us that the air flow at idle is not sufficient. I could use the high idle know bit increase engine RPM which helped some. Opening the hood also helped if I was going to be somewhere for an extended period of time. But this was not really an acceptable solution. I felt strongly that the fan clutch was not functioning properly so I discussed this with Mr. Greasy. (And later Hino techs at 2 different dealerships that looked at it). There really is not a definitive way to easily tell if the clutch is working or not but I finally decided my sanity and comfort was worth the almost $500 for a new fan clutch so I bought and installed a new one. It did not seem to make any difference at all. Not only did the air not get any colder but it did not seem to make any difference in engine temp and knowing what it is supposed to sound like, I did not hear any difference either.
Roughly 6 months after installing the new fan clutch my turbo went out. I took it to a dealership (Not either of the 2 that had looked at my fan before). While the mechanic was changing out the turbo I mentioned the fan clutch. He gave it a spin and immediately said,"This clutch is no good". I had them install a new one and send the "Other new one" in for warranty claim, (That's another story buy I did eventually get a warranty refund on that). So it seems that the new one I had first installed was likely no good right from the start. With the second new one on the truck the temps did come down some and it does seem to sound more like expected.
Air still not really cold enough - OK, now we are going all in for cold air. New A/C compressor, new condenser, new dryer, new expansion valve. Careful and 100% complete flush of entire A/C system. (Note, the dryer on this system is inside the condenser. It is individually replaceable but when you get a new condenser it comes with a new dryer installed). More improvement but still not where I wanted to be.
More discussion with the A/C shop guy and a visit to 2 different Thermo King shops. The conclusion was that perhaps the stock compressor and or stock condenser was not fully up to the task of providing the needed pressure and system cooling to provide the needed "Stuff" for both the dash and underbunk systems. After much research and discussion it was determined that there was not a feasible replacement for the compressor but enhancements could be made to the condenser part of the system.
Now to help you understand some about this I'll give a simple and partial explanation of how part of the A/C system works. When the compressor does it's job of compressing the Freon gas the gas gets hot. This hot gas needs to be cooled down in order to do it's job of making the air cold. The condenser is the part that does the cooling of the hot Freon gas. It was reasoned by those I discussed this with that perhaps there was simply not enough condenser area for the gas to properly cool. Installing a larger condenser in the factory location was not practical.
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