How many miles and when was the last time you did a basic tune-up? Its amazing sometimes what a fresh fuel filter/air filter/plugs/wires/O2 sensor/etc will do for a vehicle. Any noticible difference in how it runs that would indicate a vacuum leak or something?

ok, ill tell ya the history of this truck

She bought it over a year ago, ran great. One day it was acting like it had a broken IMG. It would just die right after start up. Well i checked it and checked it and checked it, no leak (with starting fluid) then i cleaned everything with sea foam, injector cleaner, new filters, plugs. Still died after that. Now,(months later) it doesnt die anymore, not even close, runs like a champ. So, from what i have read, it could be the fuel pressure regulator or the gasket. There are no leaks near the regulator, and no leaks on the gasket, and since it doesnt die anymore i cant figure it out. She use to say it would only die when its hot outside. So, since i cant figure it out im gonna work around it some until i find the problem.
Once i move into this house (huge warm garage) im gonna go ahead and change the gasket anyways, maybe event he regulator.
kevan

It took me about two hours. I was very prepared and reviewed everything I would be doing in advance. I used cheap, short paddle lighted toggle switches and all the materials cost maybe $20. I'm not too bright, so anyone can do this. It's much easier to find a schematic for your vehicle and just cut the wire that sends the signal to your A/C clutch in the defrost mode.

OK, anybody have a schematic? I like the idea of the defroster not turning on the AC at all, as long as I can still use the AC switch when I need it (with or without defrost).

Yeah, I like that idea too. If I still had a Trooper, I would give it a try... <img src="/forums/images/graemlins/cyclops.gif" alt="" />

Just put the switch inline with the single power wire that turns the clutch on the compressor on and off... Then, you can turn it on or off no matter what mode the system is in...

You were reading my mind. Thats exactly what I was going to say. Its much better than destroying a perfectly good switch. If you could cut the power switch at the compressor, and just run extended wires back to a switch on the dash, a lighted switch would tell you when the compressor is on or off. Only need to run 2 wires, 3 if you go with a lighted switch, third for the ground.

Dan

Guys, what you're talking about is a good way to go, but you have to find that wire first. There's a bunch of them to choose from. Then you'll be bringing high amps thru the firewall and looped thru a switch in-cab, which is not a good idea. A relay needs to be used in the engine bay to keep the high current out there where it belongs. A relay draws less than one amp and only requires one light wire thru the firewall. That's why my homegrown system is safe and works so well. I went right to the source at the fuse and can turn it off and on whenever I want in any mode. It's just like someone pulling the fuse for me when I ask for it. It's still easier to cut the right wire behind the dash or destroy the contact points of the selector switch. You don't destroy the whole switch, it just eliminates the auto A/C function and goes back to the way it was in the 70's and 80's. Whatever route you choose, it's a good thing to do. We're all capable of knowing when we need A/C in defrost and when we don't. It's the same thing with ABS. It can get me killed in the snow and even cause problems off-road on steep hills.

Mark Griffin

Which route are you talking about? There is only 1 wire going to the compressor. It's not hard to find. It comes right off the clutch and connects to the harness with a single bullet connector.



What is your idea of "high amps"? My A/C compressor fuse runs both the compressor and the internal solinoids that control the vacuum that opens the doors. The stock fuse and what is listed on the cover is 10amps. That means that the actual load on the system is less than 10 amps... probably around 6 or 8 amps. That wouldn't hurt anything coming through the firewall with a switch.

Also, if you don't buy a switch that is undesized, even if the compressor drew 20 amps, if you use a 30 amp switch, you would be fine. If you use a tiny little Radio Shack 1amp switch, yes, you will have problems... but if you use a switch designed for the type of load that will be handed out, you won't have a problem.

If you look on the compressor its self, there should be 2 wires, atleast on the earlier troops and rodeos with the 2.8s and 3.1s, one should be a power, and the other a ground. If I remember right, those wires were only 12 guage or so, not exactly heavy duty. A 25 amp switch should be fine. A lot of the newer systems are the same way. If the compressor doesnt have an actual plug, then they have a hot wire coming to the clutch, and a ground wire on the body. I would find it much easier to go through wires under the engine compartment then ripping the dash apart to find them. If you want to wire a relay in, go for it, but then you are running more wires and have to buy the relay. Not to mention you then have to find a 12 volt source to tap into, and then ground the relay and switch if you go with a lighted switch. If you want to use a relay, heres where to plug each wire on the relay using a common 5 pin auto relay:
87 - wire going to spiced compressor power wire
30 - wire comming from splice compressor power wire
85 - ground
86 - to load terminal on switch
87a - not used

For the 3 prong lighted switch:
power - to a 12 volt power source (fuse block?)
Load - to terminal 86 on relay
ground - to a good ground source.

You can go this route, but I dont think its completely necessary. Actually its probably a bit overkill. I did something similar to this to disable the TOD system on my explorer. I wanted an actual 2wd vehicle and not a permanent AWD with the ability to run 4 hi and 4 lo. Now I have awd, 4 hi, 4 lo, 2 hi and 2 lo. But I still believe you can just put a 30 amp switch inline and be fine. The lighted switch will be nice because you will know when the ac is on or off.

Dan