Low Pressure Switch and Cycling Compressor on 1998 AWD

[rmassaro]

I have a 1998 AWD Conversion. The vehicle was recently purchased from Boston area and they did not use AC much. The AC compressor did not come on when first attempted. After connecting and disconnecting the ac plug and the plug to the low pressure switch, the compressor started to cycle. Had it refilled to over 2 lbs at a garage. The mechanic and myself determined the issue was the plug at the compressor and I went home. I worked on the plug (2 small brads, some extra wire in the female end and now it is a tight seal on the males in the compressor plug. At the green wire terminal I have 13.95 VCC. At the low pressure switch there is 13.85VCC at the green wire. The ground at the firewall was dismantled and cleaned and put back together. It is a good clean ground and with a probe light on the battery, get a good light at the ground, at the black wire on the low pressure plug and the black wire at the compressor plug. However, when I check the green wires with the probe connected to the ground by the blower, it only lights at the green terminal on the compressor and not on the low pressure switch. Recheck with multimeter and there is 13.85 VCC at the low pressure plug- go figure!. If I use a paperclip and short out the plug going to the low pressure switch the compressor works continuously. If I turn the HVAC control to just vent, no ac, there is still 13.85 VCC at the low pressure switch green wire. So what exactly is the issue?

I also a 1996 AWD conversion with Polar air and checked the same spots and I get a probe light at both the compressor and the low pressure switch. So something is definitely different there- hope it is not the HVAC or the electronic module. One note: in the back seat of the van when I got it there was a box and I opened it and there is a HVAC switch- so they either recently switched it or were going to.

Also, the High position on the blower is now dead- I checked the relay and resistor pack and the red feed into the resistor pack was getting real hot and started to melt the plastic around it. If I smacked the high postion relay it would work but only for a min ute or two and then crap out. The other positions are ok. When I bypass the resistor pack completely the blower works fine.


So what do you braniacs think is the issue here?

[throrope]

rmassaro

Can't help with the refrigeration side of your conundrum, but I suspect you need a new resister pack. I lost everything a while back. I pulled the resister pack and found a main terminal corroded completely off on the inside. If memory serves, I was out of work and didn't want to spend the forty bucks for the part to do it "right." Since solder won't hold, I drilled a small hole into the leftover solid metal and connected a wire with a sheet metal screw. One of these days after old man winter packs his bags for good, I'll put it back on the list.

Good luck and keep us posted.

[a2l1]

You might want to check the continuity of the green wire from the pressure switch back. It may be something as simple as a broken wire.


A J