Aircon
Guide to retro-fit aircon (IN PROGRESS)
- While this is a fairly big job, none of the stages of the install are particularly difficult and it is well worth the effort for the comfort and convenience of air conditioning. Give yourself a full afternoon in case you come across the usual setbacks like seized on bolts but with luck it should take 3-4 hours or less.
Most of the fitting is obvious - it seems Toyota built all gen 6s with the necessary mounting points and wiring loom for aircon whether it was fitted or not, so its basically a case of obtaining all the required a/c component parts and bolting/plugging them in. You don't even need to do remove the heater control unit.
This guide is based on swapping an a/c system obtained second hand from a ’95 Jap SS2 to a ’94 UK GT but the method is similar for all variations of UK and Jap cars.
Expect to pay anything from £200 to £400 or more for a full secondhand system, depending on whether the supplier knows just how expensive it would cost new. I paid a bargain £200 from a local none specialist scrapyard. Buying everything together helps to get the best deal. You could always buy everything brand new but expect this would cost well over £1000.
If you obtain an a/c system from a car that had electronic (climate control) heater controls (instead of cable) you will need to make a couple of wiring loom modifications to its a/c cooler unit . (You will still only have manual aircon because the the two systems are too different).
If you have a choice, obtain one from a car which had normal manual a/c so it will be a straight swap.
- Before you go out and look for an a/c system or buy parts, check your car is 'aircon ready'. The easiest way is to look in the engine bay where you should find the extra plugs for the compressor and gas pressure sensor.
Compressor connection:
Gas pressure sensor connection located top right area of engine bay:
- What you need:
- ENGINE SPECIFIC PARTS: ** make sure you obtain these from a car with the same engine type as the car the system is to be fitted to (ie: 3SGE) **
Compressor , pipe work , aircon idle up valve(only needed for pre 96 ST/GT), (longer) a/c drive belt.
- NON SPECIFIC PARTS:
cooler unit (sometimes called evaporator - this is the bit that fits in the dash), aircon radiator and condenser assembly (may be supplied separate),auxiliary a/c cooling fan., a/c and econ switch covers for heater control. relays:- official Toyota part names are: relay cooling fan no.2, relay cooling fan no.3 and relay cooler (comp). (these fill the empty slots in the relay bank in the engine bay),
- EXTRA PARTS:
GT/(GT4)only - ‘smooth’ idle pulley wheel is required (2nd hand or part number 88440 20120)
ST/SR only – on the EPC I notice an additional bracket is used to hold the compressor. (2nd hand or part number 88431 12520) May already be fitted.
Check carefully all parts for damage, leaks etc especially the radiator. As previously said, getting the cooler unit from a non climate control car will ease installation.
You DO NOT need to source a heater/aircon control unit as the one already in the car has the switches for aircon (under a blanking panel). You might want to obtain the 'a/c' and 'econ' switch button covers which are approx £3 each new.
Also note that the climate control heater control units from jap imports are incompatible. (the wiring loom and other components necessary are not present)
- Stage 1: fitting the cooler unit
The cooler unit fits in place of what is essentially an empty air duct. To access it, you need to first remove the glove box (6 screws, one hidden behind passenger kick panel, remember to unplug the connectors for the glove box light as you remove it)
PICTURE – air duct
The air duct is held on by 4 screw/bolts and comes out easily. (Just watch out for all that wiring!) You’ll also need to unplug a connector that goes into it. The connector that plugs into is simply for a resistor box that gives the heater fan its different speed settings.
Before you can fit the cooler unit you need to remove and modify the blanking panel that is fitted to the bulkhead so the pipes from the cooler unit can pass through to the engine bay.
(2 bolts, accessed from the engine bay)
You will need to cut suitable holes in the rubber part of the blanking panel for the pipes. (You won’t need to if you have been given the equivalent aircon panel with the holes already there)
Now fit the cooler unit in place and plug in its two connectors into the previously unused connectors in the under dash area. Remember to re-fit the connector for the heater fan resistor box.
Don’t forget the rubber over-flow pipe on the lower of the unit that needs to pass through to the engine bay.
(If you fit a cooler unit from a climate control system you will need to swap the cooler unit’s wiring loom for the manual version - part number: 88605 2D290 (official name: Harness sub-assy, cooler wiring no.1 approx cost £20) You will also need to re-wire the top connector of the loom (this is for the thermistor). On the climate control cooler unit the connector from the thermistor has a 4 pin plug. The manual a/c system/loom uses a 2 pin plug and only needs 2 wires to be connected. You will have to join the following wires as follows: 2 pin plug green/yellow wire join to 4 pin plug green/yellow wire 2 pin plug red/white wire join to 4 pin plug white/blue wire (the one next to the green/yellow wire). You will also need to swap the resistor box from the original air duct otherwise the heater fan will only have two settings.)
- STAGE 2 – Compressor and drive belt
The compressor mounts just below the alternator and runs off the drive belt that therefore needs to be swapped for the (longer) aircon one. Notice how on the 3SGE engine the drive belt path is different with the compressor in place so the top ‘idler pulley wheel’ needs to be changed from the grooved to smooth type.
PICTURE – drive belt paths
On the GT, before the compressor can be fitted you need to remove the metal blanking piece that takes its place on non a/c equipped cars – held on by 3 bolts, 2 lower and the top bolt located on the drive belt tensioner.
ST/SR models use a bracket to hold the compressor.
Next, slacken and remove the drive belt.
PICTURE – blanking piece (+ pulley wheel)
As the compressor is quite heavy, you may find an assistant useful in helping to locate it in place (though it is possible without help, just tricky). To give yourself more space to work in and aid fitting you can remove the coolant hose from the radiator (yes you will lose most of your coolant – make sure no water gets near the compressor especially in the gas outlets) When its correctly in place you should see that the compressor and alternator wheels are aligned ready to accept the drive belt. You may plug in the compressor to the previously unused connector at this point.
Next, if required by your engine type/drive belt path swap the top ‘idler pulley wheel’ from the grooved type to smooth (held on by one nut – careful not to lose any of the washers when it comes free)
Now fit the longer a/c drive belt – slacken the tensioner more if required. When fitted be sure to re-tighten and adjust the drive belt tension to normal.
- STAGE 3 – pipe work and radiator
Most of the pipe work is obvious and will only fit one way. You may be supplied it already joined together or as completely separate parts. If you have Toyota EPC software, use it to bring up images of the whole system to help (FIG 8718 in electrical group)
(EDIT) A/C system
Where pipes join together or fit into a/c components check the rubber washer seals are present and in good shape. (It may even be a good idea to buy new seals while its in bits) The condenser and aircon radiator may already come connected up to parts of the pipe work. Because of the path the pipe takes around the engine bay, you will need to first remove the radiator, battery, air filter box and coolant level check bottle. (Again, make sure no water gets near the compressor or into the aircon system.) Luckily there is no need to remove the front bumper, but you may find you need to remove any grill you have fitted to access some of the bolts and ease installation. I found it easier to fit just the pipe work and condenser first, then slot in the aircon radiator later.
Starting at the right hand outlet of the cooler unit outlet (top right of engine bay) the path of the pipe runs down along the right side of engine bay and connects to the top of the condenser near the lower front right of engine bay. A single bolt secures condenser.
PICTURE – condenser location
It comes out of it again to the top right of the a/c radiator. Note how it passes under the front cross member.
PICTURE – pipe path
It then comes out from the lower front left of the a/c radiator and passes under the lower cross member.
PICTURE – lower front radiator under lower cross member It then goes up to the right inlet on the compressor, out of the left inlet, down, then along the lower area of the engine and then back up to the left outlet of the cooler unit via the built in pressure sensor. You may plug in the pressure sensor to the previously unused connector at this point.
Fitting the pipe work that runs along the right side of engine bay is made slightly trickier because it also needs to pass under parts of immovable engine wiring. . One the pipe work is in place, you can slot in the aircon radiator and connect the aircon pipes. The a/c radiator sits in front of the normal radiator. The mounting points for it are already there – secured by 4 nuts to the vehicle body.
- STAGE 4 – Additional jobs
Aircon idle up valve (**GT/pre-96 ST only) – this is a type of sensor that raises the idle speed slightly when it detects the aircon system is in operation. It connects to a previously unused connector that comes from near the igniter box and onto 2 previously sealed vacuum pipes in the top right of the engine bay. Its secured by a single screw.
PICTURE – Idle up valve
Relays. The aircon system requires 3 extra relays that fill the empty slots in the relay bank in the front left of the engine bay. They control the operation of the standard and auxiliary fans and compressor. Their official Toyota part names are: relay cooling fan no.2, relay cooling fan no.3 and relay cooler.
If you can’t pick them up second hand they cost around £20 each from Mr T.
Auxiliary fan. This mounts next to the fan on the back of the normal radiator. It slots in at the bottom and is secured by 2 bolts at the top. Remember to plug it in to the previously unused aux fan connector that comes from near the lower left side, near the relay bank.
Aircon control switches (interior). The A/C and econ switches are hidden under the single oblong plastic blanking cover on the heater control. Use a small screwdriver or similar to carefully to prise it off. They will work as they are, but the proper button covers for them are available from Mr T at £3 each. Part numbers: A/C: 55905 2B300 ECON: 55905 2B310
After installation is complete, it’s a good idea to check over the whole system to make sure nothing has been left of, all bolts tightened up (especially on the gas pipes) and everything plugged in. You won’t be able to tell if it works ok until its re-gassed because the pressure sensor detects the system is empty and prevents the compressor starting up. The final job is get the system ‘re-gassed’ with refrigerant by an aircon specialist (expect to pay £40 –75). They should usually perform a test to check for any leaks before putting in the ‘gas’.
If its working, when you press the A/C button you should be able to hear the compressor ‘engage’ . The cooling fans will also operate. Cooler air should be produced almost right away gradually getting colder. The compressor should be heard to switch on and off automatically when the A/C is on. With ECON on the compressor switches on for less time.
