Air Conditioning Mods?

[fltplan]

Anyone do any mods to the ac system, other than updating to R134? Would sure be nice if this thing would blow a little more air around. It is blowing cold, but just doesn't seem to get much to the upper vents.

I'm taking a trek across the desert on a regular basis, so max air is desirable. It's supposed to be 123 this weekend in the desert. Thanks, Steve

 

[tRustyK5]

The first step is to ensure correct operation. It may be you have some vents that have become partially disconnected, or a blend door that isn't closing tightly. These things usually move a good bit of air when everything is working right.

Is it all the vents that seem 'weak' or is it only a couple?

Rene

 

[fltplan]

Actually, it's mostly the top driver's vent that doesn't do much. The dash vents on the pax side are working okay and the bottom floor vents blow alot of air.

 

[fltplan]

The wife just got home from driving it and said the ac's not working at all. Ouch! I'll be out looking at that for awhile. Maybe it's just frozen up with all the humidity today. Actual rain in san diego, 98degrees.

 

[tRustyK5]

Well, there are a few AC threads going right now...and a lot of real knowledgable guys.

Rene

 

[fltplan]

Latest info. The blower isn't working in the Hi mode only. All other modes are working and compressor is putting out cold air. I did a search for air conditioning and didn't come up with anything prior to this post, but then again, I've never had too good a luck with the search function.

 

[K85 Octane]

I've never had too good a luck with the search function.

yeah, going through "titles only" is a good way, after that try "entire post"

if the thread is not titled right, or at least with some kind of keyword in it, coming across that thread is difficult.

examples"
what the heck is this
why is this happening
my k5 sounds funny

title description helps a lot!!!!

 

[Zeus33rd]

About the only real 'mod' you can do to lower vent temps is figure out how to fit a bigger condenser in front of the radiator, get a condenser with a fan mounted on it, or figure out a way to mount a fan on your current condenser. Summit sells some pretty cool stuff.

I'm not real familiar with the blower motors in these trucks, but my guess is either a bad fan control switch, or, if it's the same as a HEMTT, then the resistor/resistor pack is bad. Of course, it could be a bad blower motor too.

 

[Blue85]

If the HI speed is gone, that's the relay mounted on the side of the evap box underhood. It's easy enough to replace, but I find I can get a couple of years out of just opening it up and cleaning the contacts.

The first step in improving performance is to make sure the system is actually working right. The next thing to pay attention to is that it was vacuumed really good (and holding!) before charging. Other than that, it's a matter of getting the heat out. Electric fans help because they pull hard at idle. At high rpm, nothing can beat the mechanical fan with the clutch engaged. The cooler you get the condenser, the colder the dash air. A large parallel flow condenser works better than the stock tube style if you're interested in upgrading.

Here's a few other tricks:
-Use the VOV instead of orifice tube
-Cut off water flow to the heater core
-Seal the gap around the edge of the condenser and radiator to ensure max air flow through condenser.
-Insulate the cold underhood components
-Check/repair the seals in the underdash air handler. You want the blend door to close and seal towards cold air only. You want the fresh/recirc door to work so that MAX works as intended.
-Tint the windows
-Read the other seventyteen A/C threads

 

[fltplan]

If the HI speed is gone, that's the relay mounted on the side of the evap box underhood. It's easy enough to replace, but I find I can get a couple of years out of just opening it up and cleaning the contacts.

The first step in improving performance is to make sure the system is actually working right. The next thing to pay attention to is that it was vacuumed really good (and holding!) before charging. Other than that, it's a matter of getting the heat out. Electric fans help because they pull hard at idle. At high rpm, nothing can beat the mechanical fan with the clutch engaged. The cooler you get the condenser, the colder the dash air. A large parallel flow condenser works better than the stock tube style if you're interested in upgrading.

Here's a few other tricks:
-Use the VOV instead of orifice tube
-Cut off water flow to the heater core
-Seal the gap around the edge of the condenser and radiator to ensure max air flow through condenser.
-Insulate the cold underhood components
-Check/repair the seals in the underdash air handler. You want the blend door to close and seal towards cold air only. You want the fresh/recirc door to work so that MAX works as intended.
-Tint the windows
-Read the other seventyteen A/C threads

Thanks for the info. I'll be out of town for a week and then tackling this stuff. It's at the warehouse at work for now.

 

[fltplan]

Thanks for the info. I'll be out of town for a week and then tackling this stuff. It's at the warehouse at work for now.

Okay, cleaned the contacts on the 4 pronger. Hi works again. Thanks for the tip. I'm talking about the prongs that are on the box and the plastic plug that goes on them. I sanded the prongs and scratched the receptacle with a knife. I assume that's the part you were talking about? Anyway it worked. We'll see how long it lasts. What would need to be replaced eventually if cleaning these works? Maybe the rectangle plug/cover that is mounted to the evap box?

 

[AJMBLAZER]

Used any electrical contact grease in there? Usually works pretty good at keeping stuff like that "happy" for a long time.

 

[fltplan]

Used any electrical contact grease in there? Usually works pretty good at keeping stuff like that "happy" for a long time.

I'm gonna grab elec grease tomorrow before the trip to the river and put it on. Dry as a popcorn fart they were!

 

[fltplan]

Okay, did the de-electric grease. The Hi position works for about 5 mins, then shuts down. Unplug and plug, same thing. All other position work fine. Hi worked fine for the first 1000 miles I put on it, well it wasn't in Hi the whole time. Is it a new contact that it needs or something upstream causing this?

 

[Fordum]

Sounds like a bad switch or relay. Being a Ford man, I don't know about that relay. My truck uses the fan switch to do all the work.
The little cover in the evap box should be the resistor pack. Might cause a problem, but should not, since its not used on high.
However, DO NOT pull that pack out and run the fan. It has to be in the air stream to stay cool. If you turn the fan on any speed other than high with it out of the flow, it will turn red hot and start to fail.

One other point that no one seems to have picked up on.
You said that the bottom floor vents blow good. I'm guessing that you mean when it is in heat mode.
Double check with folks here, but I'm pretty sure the bottom vents should be closed when on AC.
If they are blowing in AC, then we just found one of your problems.

 

[Blue85]

The HI speed comes from the relay switching. It's mounted on the side of the evap box, kind of below the resistor pack. Replace the relay or clean the contacts inside. That's what I was talking about before - opening the relay and cleaning the contacts inside.

 

[fltplan]

Sounds like a bad switch or relay. Being a Ford man, I don't know about that relay. My truck uses the fan switch to do all the work.
The little cover in the evap box should be the resistor pack. Might cause a problem, but should not, since its not used on high.
However, DO NOT pull that pack out and run the fan. It has to be in the air stream to stay cool. If you turn the fan on any speed other than high with it out of the flow, it will turn red hot and start to fail.

One other point that no one seems to have picked up on.
You said that the bottom floor vents blow good. I'm guessing that you mean when it is in heat mode.
Double check with folks here, but I'm pretty sure the bottom vents should be closed when on AC.
If they are blowing in AC, then we just found one of your problems.

It's definitely blowing ac out of the two floor vents on top of the tranny tunnel. I thought this was normal.

As far as the relay, I will take a look on the side of the evap box. I tried pulling the rectangle box apart on the side of the evap box. Didn't seem to want to budge. Then I found the plug and everything was fine temporarily. I'll post up a pic here in awhile and we'll confirm what I'm looking for. Thanks.

 

[Blue85]

If there air comes from the wrong places you either have a problem with the levers/seals in the air handler or there is a broken vacuum line. Other than the compressor running, does anything change as you cycle from Max/Bi/Norm/Vent/Heat/Def?

 

[fltplan]

Okay, here's a couple pics, so I can clarify what I'm supposed to be looking at.

I have removed the triangle plug by the caution sticker, cleaned the conectors, put some di-electric grease on and it works for a short period. I assume that you guys are talking about the box just below and to the right of the plug? That didn't want to come apart when I was messing with it originally. If that's what I should be working on, then I'm sure I can get it apart.

 

[Fordum]

I think so. Like I say, Fords don't use that relay. But they do use the same resistor pack.

If you want, you can take the small screw out and remove that plate with the plug next to the warning sticker.

You will find the resistor pack under there.
It will sometimes have problems with loose connections, but those will only affect the lower speeds.
Full speed bypasses it.
But while you are there, you might as well familiarize yourself with it. So you will know what to look for if you lose a lower speed.

Just do not turn the fan on with the pack out of the case cause it needs the air flow to stay cool.