When we left off last month, I’d pulled all the stock heater junk out of the truck and installed the condenser and dash vents, as well as the firewall block-off plates that covered the void left from the OEM heater box assembly. Returning to the project this month, we’ll begin by installing the evaporator core under the dash along with the ducting to each vent. From there we’ll wire the unit up starting under the dash and working our way towards the battery, hooking up the binary switch, grounds, and compressor. Since the SureFit kit comes ready to rock from Vintage Air, all the hoses and lines are cut to fit so it’s a simple matter of mating each end to their respective connection and we’re ready to charge the system.
One of the neatest features of the SureFit kit is the ability to use the stock A/C control unit, without the mechanical cables that the stock system used. Instead, Vintage Air utilizes a patented, ingenious cable converter system that sends the location of each switch electronically to the corresponding actuator. For example, when the fan switch is slid to “high,” the fan motor receives a signal telling it to turn on to its highest setting. This makes wiring the system a simple plug-and-play procedure and yields a very user-friendly control system once the panel is properly calibrated.
After completing the install, it was time to charge the system. This is best trusted to a certified A/C mechanic with the proper equipment as the system needs to be evacuated to remove any moisture that might be present before being charged using 1.8 pounds (28.8oz.) of R134a refrigerant. Once charged, the high-side pressure should read between 160-250 psi while the low-side pressure should be between 6-12 psi in a steady state. Center duct temperature should be between 36-46 degrees Fahrenheit. If your system matches these parameters, you’re good to go!
I put the system to the test right off the bat, blasting off from the office on a 90-degree late Summer day to sit on the 405 freeway during rush hour Southern California traffic. This time though, I was prepared and managed to sit in traffic in a state that I’ve never been accustomed to, comfort. With the A/C set to cold and the fan on medium, sitting in traffic with the sun beating down on the truck, it really didn’t seem all that bad. In fact, it was quite tolerable. Actually, it was comfortable. What usually would have been a miserable experience was made quite pleasant given the fact that I could keep the windows rolled up and adjust the temperature of the cab to suit my taste. I think I could get used to this kind of commuting. CCT
Picking up where we left off...
Picking up where we left off last month, the rear bracket is attached to the evaporator …
… as well as the hard lines...
… as well as the hard lines and front bracket. Don’t forget to lube the O-rings prior to installation! The lines are, from the top, #10 suction, #6 liquid, heater to water pump, heater to intake.
After the #10 suction line...
After the #10 suction line is installed, the entire line is wrapped with the supplied press tape to cover any exposed metal. This prevents condensation buildup from happening due to the extremes in temperature between the refrigerant and the interior of the cab.
With the evaporator mounted...
With the evaporator mounted loosely to the firewall via the rear bracket, the front bracket mounting holes are transferred to the cowl area, then drilled 3⁄16-inch.
Once the evaporator is securely...
Once the evaporator is securely mounted, the premade hoses can then be routed. The #10 suction line attaches to the appropriate fitting on the compressor while the #6 liquid hose runs forward to the #6 drier line. The #8 fitting on the compressor mates to the condenser line under the battery tray.
Back inside the cab, the duct...
Back inside the cab, the duct hose is routed to each duct according to the schematic provided. The two diagonal ducts on the evaporator run to the defrost ducts via 2-inch hose while the three 2 1/2-inch outlets on the left run to the center, passenger side, and driver side from the top respectively.
Wiring the system is pretty...
Wiring the system is pretty straight forward. The red wire coming from the evaporator connects to one end of a 30AMP circuit breaker mounted as close as possible to the battery while the white lead connects to BATT NEG.
Two relays are supplied and...
Two relays are supplied and can be mounted near the evaporator; the heater control valve relay and A/C compressor relay. The heater control valve relay is wired to one side of the heater control valve by a green wire while the other side connects to the 30AMP circuit breaker up near the battery. The 30AMP circuit breaker is connected directly to 12V. The white wire running from the heater control valve goes to chassis ground.
The A/C compressor relay connects...
The A/C compressor relay connects via a blue wire to the binary safety switch. The black wire that exits the compressor housing connects to the opposite side of the binary switch.
The violet wire on the evaporator...
The violet wire on the evaporator harness connects to IGN while the white wire runs to the BATT NEG. In our case, the brown wire is the old POS heater wire that runs from the key switch so it was a simple matter of plug and play to get IGN power to the system.
The main harness plugs into...
The main harness plugs into the front of the evaporator. The empty space on the right is where the control wiring harness will plug in a bit later.