Tearing down my HJ47 troopy (2 Viewers)

[Bowling4$]

I just want to thank you for one of the best build threads that I have ever read. I am in the process of getting an 84 HJ47 and this was inspirational. Taking all the pictures and journaling the entire build is greatly appreciated. Where else do you get a community so willing to help each other? Thanks!

 

[gswest]

Thanks for your input. I get so much information from this site that anyone who gets something from reading about my trials and tribulations is a bonus. Remember to do the same when you start your project. We all love to see the process of how we each tackle similar issues. The more pictures the better. In the end, this is a journal of what I did to this truck. I made mistakes and had to do things over and sometimes over again. I used the site to help myself. People here continually came to my rescue. Hopefully, this website stays around or at least the information stays accessible for a long time so people can use it for a reference.
PS, Can you help raise my bowling average? My average is 100, + or - 20 or so?

 

[Bowling4$]

I hate bowling just seemed like a good name

 

[gswest]

OH, no bowling help? Crap! Were all about the bowling.

 

[gswest]

I got the A/C charged today. The first time I tried they (A/C shop) told me the blower wouldn't turn on. So I did some creative wiring and the blower turns on. Unfortunately the compressor doesn't turn on. Since it's new, I figured the same grounding issues that the heater blower was having has something to do with the A/C problem. Anyway, I jumped a positive wire and the compressor came on and we have cool air. I have to decide whether I want to deal with this like I did with the heater blower (bypass the switch with a toggle switch) or take the original switch back out and start a troubleshooting process (which I'm clueless about). One thing I know is, there is no juice going to the compressor. I pulled the wiring off and checked the wiring harness connection where it connects to the compressor wiring loom. There's no power there. But the A/C blower comes on, albeit not very forcefully. I paid $150 bucks to have my shop install a couple of R-134 adaptors, the PAG oil and the freon and an hour of labor to get it ready to cool. But I wasn't going to pay them to troubleshoot it. That could have taken a while, which = $$$. At least I know I can make it work, but obviously I'd rather have it working thru the original wiring which incorporates a fuse and a switch on the freon line that I assume shuts off the compressor if you lose all freon. I need a Cruiser A/C guy! I'll start perusing this site for some info.

 

[gswest]

I looked through the wiring to my A/C compressor and pulled the connections off the A/C controller. There's no obvious bad wires, but there's no power going to the compressor. For now (and maybe forever) I've run a switched and fused wire to the compressor. It works and we have cold air coming into the cabin. A good mechanic could probably figure out what my problem is, but I'm calling in good for now. The pic shows the rather unglamorous toggle switch. The original A/C controller does turn on the A/C fan, just not the compressor. The heater blower works and the A/C works. On to the next fix, the front differential.

 

[MrMoMo]

Totally un-associated with landcruiser HVAC systems, but often the systems we install on boats have two switches in series with the clutch switch... 1st is for refridgerant pressure... If it's too low, the compressor won't come on. Second is for temperature - if it's too cold, the compressor won't come on.

No idea if the cruiser HVAC system has these switches, but if you can trace the wiring back, you may find a faulty switch, or a faulty connection at one of these switches that is preventing the system from allowing the compressor clutch to kick on...

 

[whitey45]

There is usually a high and low presure switch to bring the comp on and off, it needs to cycle on and off to work properly! Love the build!

 

[lostmarbles]

Hi Scott

This is for a 1983 HJ-series in case it is of any use:

 

[waiting for time]

The compressor is switched on and off by the amplifier based on the temperature of the evaporator. If you leave the compressor on full time the evaporator will freeze up and the pressure in the system exceeds the max pressure of 15 bar. Normaly there are 3 switches in the system that need to have their vallues within range, upper and lower pressure and evap temp.

 

[gswest]

Wow, thanks guys. This may be way over my head. I see the switch that is on the refrigerant line but I'll have to look to see whats connected to the evaporator. I wouldn't be surprised if something is wrong with the switch coming off the fluid line since the copper line has been sitting there for 3 or 4 years disconnected from everything. I may have to get an A/C specialist in on this one. But, I will trace the wiring to these switches. I can say that the wiring going to the switch on the copper line has no power at all. So, I would guess that if that switch was the problem, I'd at least have power going to it, but not out of it. No?

 

[waiting for time]

Check the relais first.

 

[lostmarbles]

The compressor is switched on and off by the amplifier based on the temperature of the evaporator. If you leave the compressor on full time the evaporator will freeze up and the pressure in the system exceeds the max pressure of 15 bar. Normaly there are 3 switches in the system that need to have their vallues within range, upper and lower pressure and evap temp.

I don't agree with what you've said in the little bit I've highlighted in orange Michael.

If the compressor is allowed to keep running when the evaporator has already accumulated a lot of frost, the pressures (both high side and low side) would actually keep falling. (Neither of them would rise.)

But this fall in evaporator temperature/pressure would create it's own problems:

• The refrigerant flow would drop to the point where oil (that normally circulates with the refrigerant) would get trapped in the evaporator (because it would get so viscous/cold there and the flow rate need to carry it back out would be too low). This would starve the compressor of lubrication, and
• The frost layer would increases to the point where it would block the gaps between the evaporator fins, thus decreasing the flow of cold air into the cabin (ie. stopping the evaporator from working) and making the evaporator temperature, refrigerant flow rate and refrigerant pressures further plummet.

So that thermostat (that has its sensor attached to the cold evaporator fins/tubes) wouldn't actually cause high refrigerant pressures if it were to fail in the closed-contacts position but it would indeed still cause problems (as outlined above).

Wow, thanks guys. This may be way over my head. I see the switch that is on the refrigerant line but I'll have to look to see whats connected to the evaporator. I wouldn't be surprised if something is wrong with the switch coming off the fluid line since the copper line has been sitting there for 3 or 4 years disconnected from everything. I may have to get an A/C specialist in on this one. But, I will trace the wiring to these switches. I can say that the wiring going to the switch on the copper line has no power at all. So, I would guess that if that switch was the problem, I'd at least have power going to it, but not out of it. No?

Post a pic of the switch that's disconnected (and on one of your refrigerant lines) Scott so hopefully we can then determine if it is a high pressure cut-out or a low-pressure cut-out.

(Note: My wiring diagram doesn't show a high-pressure cut-out switch but all large refrigeration/AC systems have them and many small ones do as well. So you never know.... Perhaps you have one too).

If that's you're low pressure cut-out switch that's disconnected then I certainly wouldn't recommend running it like that..

The evaporator-temperature-sensing thermostat (aka low temperature cut-out switch) is normally adjustable and is normally what you actually twiddle with to select colder or warmer settings. So if your system has one of these, just check behind it to see if you can spot a length of capillary-tubing coming out the back. If you can, follow it with your eyes and you should find the far end of it embedded somewhere in your evaporator fins where it should be sensing your evaporator temperature.

Failure of this thermostat is not uncommon. And since it is operates by means of a pressurised fluid that controls a bellows that operates a set of electrical contacts .... any leak in the sensor capillary line means that the thermostat will think the evaporator is completely frosted over (and so it will INSIST the compressor isn't allowed to start up). ..... because low temperature equates to low pressure when your dealing with saturated vapours .... which is what you have, or SHOULD have I should say, inside that thermostat capillary tubing that entends in to touch your evaporator fins/tubes.... (What I'm saying here in this dribble...is that these thermostats normally fail in the "open-contacts position" and that such a failure could well explain why your magnetic clutch won't engage without your extra live-wire feed.)

 

[waiting for time]

Just start with the basics, is the amplifier recieving power. Check the switch and go from there. Next are the relais. Never had problems with the temp censor on a Toyota AC.

 

[gswest]

Where is the amplifier? My manual doesn't have any info on the A/C. Tom's wiring diagram shows the amplifier, but I'm at a loss as to what and where that part is. It's not the controller, right?

 

[lostmarbles]

Where is the amplifier? My manual doesn't have any info on the A/C. Tom's wiring diagram shows the amplifier, but I'm at a loss as to what and where that part is. It's not the controller, right?

I'm guessing it's a printed circuit board with quite a few electronic gismos on it that is with your temperature control dial in some sort of enclosure...

But I'm working relatively blind here because I have never owned a Toyota/Nippondenso factory A/C system (only an aftermarket version)....

My wiring diagram shows a "volume switch" and "thermistor" too ... so perhaps these together serve as the "thermostat" and therefore take the place of "the capillary tube filled with saturated vapour" that I mentioned above.

Michael may well have a better idea on this.



PS. While my background is in refrigeration/airconditioning .... I specialised in "industrial/commercial" and so I seldom worked on motor-vehicle AC (and never wanted to start either because it is a PITA).

 

[waiting for time]

I actualy worked with OEM Toyota AC units. Build over a 100 units in all kinds of Toyota's. No classic LC's. It's been over 20 years so I have to dig in my memory. The amplifier is a small box. You can find it when you follow the wires behind the AC knob. Take a few pictures it will help my memory.

 

[gswest]

Ok, I'll take the controller out of the dash and start from there. This is much appreciated information guys. I'm not going to run it anymore hot-wired as it obviously may cause a failure. I can't remember any sensor on the evaporator but I do have a plug that seems to go nowhere. I'll post up some picks later today of the switch on the refrigerant line and the plug to nowhere. As well as the controller.
Thanks!

 

[gswest]

I got the A/C controller out and took it apart. I plugged it back in and turned on the power but didn't start the engine; it showed voltage on both sides of the switch that turns on the compressor and controls the cooling temp. But when I turned on the engine, it showed almost no voltage, maybe 2 volts. So I took the controller apart and the only thing I can see that looks unusual is the brown spot in one section of the circuit board. Is this a indication of a short circuit? Or whatever you would call a burned out section of the circuit. I'm posting a pic of that switch on the coolant line and the wire section that ends with no mate. Also a pic of the circuit board with questionable brown section on the upper right quadrant.

 

[waiting for time]

Second picture is not very clear, looks like the high/low switch. Maybe a different angle will help.
You should check the connection/switch connected to the blower switch, the AC will only work if it gets a signal that the blower is switched on. Can't see if there is something wrong with the amp, what is on the other side of the print? Can you post a pic that shows a larger area of pic 3?