Tuscan Heater and Fan Controller
Discussion
Hi All
I've had a problem with my heater controls - they only worked intermittently. The LEDs on the control panel would go out and the whole heater was dead, and then they would magically appear again without rhyme or reason.
I did the search in here and know about the burning out earth wire, but there was no trace of that. I fiddled with the wires, mainly pushing then into the block to see if it was a bad connection, but there was no consistent "touch wire X and it works every time". I ended up stripping the controller and ringing out the connections to look for bad joints. There doesn't seem to be much information on here, so I'm adding the strip procedure and pin-outs between plug and board in the hope it helps anyone else. The problem was dry joints on the connector at the main board.
Word of warning, this only relates to the original controller in the Mk1. (0429). You should also take electrostatic precautions with the circuit board by earthing the case.
Heater controller is mounted under the passenger dash, it is a black metal box about 6cm x 8cm x 10cm - mine was on the left mounted on a small bracket using two of the four screws holding one end plate on. Note the orientation.
Remove the screws and gently pull the box free and down into the footwell. As with all cables, bend the gently if you need to.
Disconnect the cable using two release catches. The plug is keyed so that it can only go in one way, with one V cutout on one side vs 2 V cutouts on the other. The controller will have 24 pins (4 x 6) sticking out from the connector.
Remove the controller to a bench, or something to work on. You will need a medium and small crosshead screwdriver, and a multimeter. The central pins are hard to get to, so you need something to extend them. I used an old bullet connector socket.
remove the two remaining screws at one end of the case, and then the equivalent four screws at the other end. Do not touch the two screws next to the connector block.
On the bottom of the box will be a small nut. The holds a component onto the inside of the case which acts as a heat sink. On the opposite side of the box is a hole. Use the small cross head screwdriver to reach down through this to the screw, and then remove the nut. Keeping the screwdriver tight in place, turn the box upside down and lower the screw down and out of the box on the end of the screwdriver.
The connector/daughter board will now slide out bringing the main board with it (mounted at 90 degrees). On one side of the main board are two capacitors (look like two round batteries). Turn the board over so they are facing down with and have the connector pins pointing towards you. On the edge of the main board nearest to you are a row of 18 short pins, a gap and then a shorter row of 6. This is where the 24 pins on the connector enter the main circuit board.
With the multimeter set to Ohms, check each connection using the picture here. Note that other pins may give a value other than 0 or open, the table shows where it should be 0. Note than any connectivity problem could be on the main board, or on the back of the daughter board. Also note that on the main board you should measure against the base of the solder around the pin and the pin itself, not on the pin itself otherwise dry joints could be missed.
In true Haynes fashion, re-assembly really is is the reverse of dis-assembly - work upside down to get the component screw and nut back and note that there should be a thin plastic sheet between the component and the case - this may be stuck inside the case with the white heat paste.
Hope this helps someone.
Konrod
I've had a problem with my heater controls - they only worked intermittently. The LEDs on the control panel would go out and the whole heater was dead, and then they would magically appear again without rhyme or reason.
I did the search in here and know about the burning out earth wire, but there was no trace of that. I fiddled with the wires, mainly pushing then into the block to see if it was a bad connection, but there was no consistent "touch wire X and it works every time". I ended up stripping the controller and ringing out the connections to look for bad joints. There doesn't seem to be much information on here, so I'm adding the strip procedure and pin-outs between plug and board in the hope it helps anyone else. The problem was dry joints on the connector at the main board.
Word of warning, this only relates to the original controller in the Mk1. (0429). You should also take electrostatic precautions with the circuit board by earthing the case.
Heater controller is mounted under the passenger dash, it is a black metal box about 6cm x 8cm x 10cm - mine was on the left mounted on a small bracket using two of the four screws holding one end plate on. Note the orientation.
Remove the screws and gently pull the box free and down into the footwell. As with all cables, bend the gently if you need to.
Disconnect the cable using two release catches. The plug is keyed so that it can only go in one way, with one V cutout on one side vs 2 V cutouts on the other. The controller will have 24 pins (4 x 6) sticking out from the connector.
Remove the controller to a bench, or something to work on. You will need a medium and small crosshead screwdriver, and a multimeter. The central pins are hard to get to, so you need something to extend them. I used an old bullet connector socket.
remove the two remaining screws at one end of the case, and then the equivalent four screws at the other end. Do not touch the two screws next to the connector block.
On the bottom of the box will be a small nut. The holds a component onto the inside of the case which acts as a heat sink. On the opposite side of the box is a hole. Use the small cross head screwdriver to reach down through this to the screw, and then remove the nut. Keeping the screwdriver tight in place, turn the box upside down and lower the screw down and out of the box on the end of the screwdriver.
The connector/daughter board will now slide out bringing the main board with it (mounted at 90 degrees). On one side of the main board are two capacitors (look like two round batteries). Turn the board over so they are facing down with and have the connector pins pointing towards you. On the edge of the main board nearest to you are a row of 18 short pins, a gap and then a shorter row of 6. This is where the 24 pins on the connector enter the main circuit board.
With the multimeter set to Ohms, check each connection using the picture here. Note that other pins may give a value other than 0 or open, the table shows where it should be 0. Note than any connectivity problem could be on the main board, or on the back of the daughter board. Also note that on the main board you should measure against the base of the solder around the pin and the pin itself, not on the pin itself otherwise dry joints could be missed.
In true Haynes fashion, re-assembly really is is the reverse of dis-assembly - work upside down to get the component screw and nut back and note that there should be a thin plastic sheet between the component and the case - this may be stuck inside the case with the white heat paste.
Hope this helps someone.
Konrod
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