Hi All, My heaters are not working. Never normally use them but we were going to bleed the cooling system and found out when I turn the heater on there is no heat. The hot cold know is working fine with the correct ohms both cold and hot. The brown wire going to the heater control valve is at a constant 12V no matter what we do. I remember there being a control relay but for the life of me I cannot remember where it is. I should also point out I cannot hear the AC compressor click when I turn it to fully cold. There is no gas in the AC as we have not been able to source some R12 refrigerant. No idea if this is linked or due to having no gas in the system. Thanks Craig.
This is good and as it should be. This is also good , but only confirms that the signal you are sending the the AC ECU to request hot or cold is working. You also need to confirm that the other sensor signals going to the AC ECU are also OK -- i.e., do all of the AC sensor tests on pages H29 & H30 of the TR WSM. The AC system relays are mounted on the lower left of the AC unit itself (to the right of the LHD acc pedal behind the center tunnel side panel - items 16 and 17 here (item 15 is a timer IIRC): Image Unavailable, Please Login Let me warn you that the schematics shows these relays "changed" over the TR years/versions and were specified by the AC vendor and not Ferrari -- so some may be odd ball relays (which can require moving the wires around in the relay socket to replace them with a non-oddball relay). The logic of this system is: When the STOP pushbutton is pressed = the MB (brown-white) wire at the hot water vale is always held at ground by one of those relays = the hot water valve is always closed. When any other pushbutton is pressed = the relay connected to the MB wire actuates = releases the MB wire from always being ground, and the MB wire is now controlled by the AC ECU to be ground to not add heat or to not be ground to add heat. This is normal for a system with no refrigerant as the high/low pressure switch will be open. To make this test with no refrigerant, you'll need to connect the two wires of high/low pressure together with a jumper (simulating a closed high/low pressure switch), and just do this test briefly. PS Relay G in the main fuse-relay panel is the main power supply relay for the AC system -- if your cabin air blower motor is working = relay G is OK. If your cabin air blower is not working (when a pushbutton other than STOP is pressed) = either relay G is bad or the connection in the k white horizontal connector is frazzled/burned.
Thanks guys. Steve I'll have a good look through the other WSM pages as you've suggested. I've found the relays and they look identical to what the image above shows.
