Picnic A/c Problem

January 15, 2008

Hi all,

Got an a/c problem on my 1999 2.0 Picnic GLS.

The system is gased OK as I had that done not so long ago, but now it has stopped working and the a/c light just flashes after about 5 seconds of turning the system on. The compressor clutch is not engaging either.

Has anyone else come across this problem?

Has anyone got a diagram of the Toyota a/c system anyware?

Thanks in advance,

John

January 15, 2008

the flashing usually means that although the system is gassed, the pressure inside the system is not sufficient. There is a pressure switch somewhere on the system that needs to be tripped to let the system work correctly and enable the clutch. It's most likely that you've lost a bit of pressure somewhere ( possibly a slow leak ). I've never heard of a pressure switch failure, but there's always a first time I suppose.

Good luck !

January 22, 2008

Well got the system regassed etc today and it's not the gas, as 750g went back in.

The a/c light still flashes about 5 secs after depressed and the compressor clutch doen't engage. If you pull the pressure switch plug off (4 wires) the electric fans kick in and the engine idle increases, and a clunk is heard from around the compressor (clutch?), the reverse happening when the plug is put back on. The Light still flashes though.

Going to call the dealer to find out the price of the 4-wire switch in the morning, a small fortune I would expect!

May 16, 2008

Well got the system regassed etc today and it's not the gas, as 750g went back in.
The a/c light still flashes about 5 secs after depressed and the compressor clutch doen't engage. If you pull the pressure switch plug off (4 wires) the electric fans kick in and the engine idle increases, and a clunk is heard from around the compressor (clutch?), the reverse happening when the plug is put back on. The Light still flashes though.
Going to call the dealer to find out the price of the 4-wire switch in the morning, a small fortune I would expect!

I have the same problem with the Air con on my Picnic, did you get it resolved? what was the problem any help would be appreciated, cheers Meyerman

May 16, 2008

Hi Meyerman,

I haven't got any further than before as I haven't called the dealer yet. Maybe between us we might solve this.

Have you had yours regassed yet?

When I have the engine running and activate the a/c, the clutch on the compressor tries to kick in then snaps out, with the green light flashing. On removing the connection to the pressure switch (to the righ of the a/c rad with 4 wires in it, near to the spyglass) the revs change, and change again when I reconnect.

The switch maybe duff, as there are a few sites, especially in the USA, that list loads of pressure switches for lots of cars, Toyota also, so there is obviously a problem with them sometimes.

What I don't want to do is to replace the switch, then find that it is another fault entirely.

I do know that a mechanic that I used before did bypass the pressure switch and got the compressor clutch to operate and the car cooled down OK. Maybe it is the switch in the end.

John

May 18, 2008

you are discribing the same problem i had with mine last week the fault on mine turned out to be a broken wire on the plug that connects to the clutch this is located just bellow the top pulley on the cam belt hope this helps

June 2, 2008

John It seems the problem is indeed the pressure switch, my auto electrician has done a load of checks & isolated the problem to the pressure switch, have ordered a new 1 from Toyota £89.95, not a cheap item but will be worth it when A/C is back up & running. Cheers Karl

Hi Meyerman,

I haven't got any further than before as I haven't called the dealer yet. Maybe between us we might solve this.

Have you had yours regassed yet?

When I have the engine running and activate the a/c, the clutch on the compressor tries to kick in then snaps out, with the green light flashing. On removing the connection to the pressure switch (to the righ of the a/c rad with 4 wires in it, near to the spyglass) the revs change, and change again when I reconnect.

The switch maybe duff, as there are a few sites, especially in the USA, that list loads of pressure switches for lots of cars, Toyota also, so there is obviously a problem with them sometimes.

What I don't want to do is to replace the switch, then find that it is another fault entirely.

I do know that a mechanic that I used before did bypass the pressure switch and got the compressor clutch to operate and the car cooled down OK. Maybe it is the switch in the end.

John

June 2, 2008

Hi Meyerman,
I haven't got any further than before as I haven't called the dealer yet. Maybe between us we might solve this.
Have you had yours regassed yet?
When I have the engine running and activate the a/c, the clutch on the compressor tries to kick in then snaps out, with the green light flashing. On removing the connection to the pressure switch (to the righ of the a/c rad with 4 wires in it, near to the spyglass) the revs change, and change again when I reconnect.
The switch maybe duff, as there are a few sites, especially in the USA, that list loads of pressure switches for lots of cars, Toyota also, so there is obviously a problem with them sometimes.
What I don't want to do is to replace the switch, then find that it is another fault entirely.
I do know that a mechanic that I used before did bypass the pressure switch and got the compressor clutch to operate and the car cooled down OK. Maybe it is the switch in the end.
John

June 2, 2008

Well I think I will give it a try as well, as there is a definate change in the engine note etc when the switch is disconnected. I will let you know how mine works out.

John

June 13, 2008

Hi john. The saga continues, pressure switch replaced whcih required a re-gas. Unfortunatly now there is no power at all to the dashboard switch. Auto elec thinks there now might be a problem with another part of the system as half of it works and has power to it. Trying to locate a wiring diagram for the electrics for the airco nto the picnic. Any ideas?

Cheers Karl

June 17, 2008

Hi john. The saga continues, pressure switch replaced whcih required a re-gas. Unfortunatly now there is no power at all to the dashboard switch. Auto elec thinks there now might be a problem with another part of the system as half of it works and has power to it. Trying to locate a wiring diagram for the electrics for the airco nto the picnic. Any ideas?
Cheers Karl

Good luck trying to find one on the net, I've had no luck so far. Guess it might only be a Jap specialist or the main dealer. Checked all the fuses already I guess.

John

June 20, 2008

This problem with the air con is becoming extremly difficult to deal with. The pressure switch has been replaced & system fully regassed, now there is no power at all to the dashboard switch. There is power supply to the Air con amplifier but no power from the amp to the switch etc. Finding a wiring diagram is about impossible. The system operates on a 3 wire system, quite differant to the celica & Rav4 which are 4 & 5 wire systems. I suppose a possibility could be a faulty Air con amp but it does seem strange thatprior to re-gassing the system operated though wouldnt work due to gas loss when replacing the pressure switch.

Does anyone out there have any suggestions, both me & Auto Elcetrician are scratching heads now, toyota dealer not really helpful they havnt got a wiring diagram. ANY HELP would be APPRECATED thanks in anticipation. Karl

August 13, 2008

This problem with the air con is becoming extremly difficult to deal with. The pressure switch has been replaced & system fully regassed, now there is no power at all to the dashboard switch. There is power supply to the Air con amplifier but no power from the amp to the switch etc. Finding a wiring diagram is about impossible. The system operates on a 3 wire system, quite differant to the celica & Rav4 which are 4 & 5 wire systems. I suppose a possibility could be a faulty Air con amp but it does seem strange thatprior to re-gassing the system operated though wouldnt work due to gas loss when replacing the pressure switch.
Does anyone out there have any suggestions, both me & Auto Elcetrician are scratching heads now, toyota dealer not really helpful they havnt got a wiring diagram. ANY HELP would be APPRECATED thanks in anticipation. Karl

I found debcon's post helpful. Had the same problem on my 98 picnic (light on for 5 seconds them flashed). Looked at all the connections, there's a small electrical connector on top of one of the units in the engine (near the front) which has 3 small wires going into it. One was indeed broken. All 3 wires enter the unit through a tiny cylindrical rubber bung or gromit. You can only see the round top of this when it's in situ. I removed the male/female unit to make access easier, pulled out the gromit with the broken wire (carefully - didn't want to break more wires) stripped off some of the insulation to expose the metal wires, pushed the wire back through the bung, and the bung into the hole, so the wire is held in contact by the bung. It worked perfectly for 1,200 miles across France.

September 25, 2009

This problem with the air con is becoming extremly difficult to deal with. The pressure switch has been replaced & system fully regassed, now there is no power at all to the dashboard switch. There is power supply to the Air con amplifier but no power from the amp to the switch etc. Finding a wiring diagram is about impossible. The system operates on a 3 wire system, quite differant to the celica & Rav4 which are 4 & 5 wire systems. I suppose a possibility could be a faulty Air con amp but it does seem strange thatprior to re-gassing the system operated though wouldnt work due to gas loss when replacing the pressure switch.
Does anyone out there have any suggestions, both me & Auto Elcetrician are scratching heads now, toyota dealer not really helpful they havnt got a wiring diagram. ANY HELP would be APPRECATED thanks in anticipation. Karl

Hi Karl,

I did replace the pressure switch in the end and like you no joy. I do still have power to the swirch inside the car though.

In reading the other replies I am tempted to have a look at the wiring harness by the plug connection, as I cannot make it any worse...and it might even fix the fault just in time for the autumn!

Did you sort yours out eventually?

John

June 16, 2010

Did any one ever manage to get their Picnic a/c working again? Starting to get warm and I would like it back working. Never did get to look at the wiring harness to see if there was a fault there, maybe that would be the place to start looking... :rolleyes: