tomaco1 Posted September 21, 2008 Share Posted September 21, 2008 I got my "new american style heater" and need a little help with the wiring, and what to do with the vacuum hoses? My old system(110 style) had 4 speeds with a separate line and fuse for 4 speeds, There is a relay and a 3 connector wires on top of the heater box. There is also the vacuum hoses that run from the heater core line to the top of the heater box? Do I need those anymore? The new heater has 3 wires:1) green 2)green/yellow 3)purple/green Thanks in advance Quote Link to comment Share on other sites More sharing options...
pete3000 Posted September 21, 2008 Share Posted September 21, 2008 As you already know your old heater is actually an aircon fan unit with the associated switch (creamy plastic thingy) and relay to switch your a/c pump in. by swapping the "other heater unit" you will lose the a/c. Right the wiring for the new one. the purple/green is a live feed which is needed from the vehicle fuse box when you key is on at pos 1 or greater. the other two are returns to go to the cab switch for speed 1 and speed 2. They are the other side of the fan and one has a resistor for your slow speed inline. These are taken to ground by the cab lever switch which should have a black lead connected to its common or wiping contact. It wont hurt to touch these two green wires to ground one at a time to see which is which. You don't say if your aircon has packed in or you are stripping it out but, take care if disconnecting pipes with refrigerant in. It would be worth taking pump off and removing drive belt to save a few bhp. not sure how cab unit is bolted/piped in but this may also give more leg room if removed. Pete Quote Link to comment Share on other sites More sharing options...
tomaco1 Posted September 21, 2008 Author Share Posted September 21, 2008 Thanks, My a/c system is housed entirely under the hood,the heater core and a/c are in the same box. Does the newer style heater fan only have 2 speeds? As you already know your old heater is actually an aircon fan unit with the associated switch (creamy plastic thingy) and relay to switch your a/c pump in. by swapping the "other heater unit" you will lose the a/c. Right the wiring for the new one. the purple/green is a live feed which is needed from the vehicle fuse box when you key is on at pos 1 or greater. the other two are returns to go to the cab switch for speed 1 and speed 2. They are the other side of the fan and one has a resistor for your slow speed inline. These are taken to ground by the cab lever switch which should have a black lead connected to its common or wiping contact. It wont hurt to touch these two green wires to ground one at a time to see which is which. You don't say if your aircon has packed in or you are stripping it out but, take care if disconnecting pipes with refrigerant in. It would be worth taking pump off and removing drive belt to save a few bhp. not sure how cab unit is bolted/piped in but this may also give more leg room if removed. Pete Quote Link to comment Share on other sites More sharing options...
pete3000 Posted September 21, 2008 Share Posted September 21, 2008 yup, the slider does nothing electrical till it is near the bottom of the slide, then the first click (speed1, very slow) then speed 2, slow. Like a film I saw where the donkey was a deluxe 3 speed slow, very slow and stop. The mechanical slider opens the air flap for manual intake of air into heater, unitl the fan works at the bottom. (optimistic idea at best). Temperature control works by bypassing the heater matrix or not IIRC. Pete Quote Link to comment Share on other sites More sharing options...
tomaco1 Posted September 21, 2008 Author Share Posted September 21, 2008 I wonder if I could somehow use my old 4 speed switch with the new heater? yup, the slider does nothing electrical till it is near the bottom of the slide, then the first click (speed1, very slow) then speed 2, slow. Like a film I saw where the donkey was a deluxe 3 speed slow, very slow and stop. The mechanical slider opens the air flap for manual intake of air into heater, unitl the fan works at the bottom. (optimistic idea at best). Temperature control works by bypassing the heater matrix or not IIRC. Pete Quote Link to comment Share on other sites More sharing options...
western Posted September 21, 2008 Share Posted September 21, 2008 the left hand slider is meant to be a resistor, so the motor runs at various speeds, with the bottom 2 clicks as a continuos speed slow & 2nd click as a fast spped. Quote Link to comment Share on other sites More sharing options...
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