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This may be well known but I couldn't see it anywhere.
1) Bought T5 cab chassis
2) Found vent control knob defective (the one that directs air at face, floor, etc). It wouldn't direct air and made awful 'broken' sounds as it was turned.
3) Pulled out assembly (the two knobs plus air con and recirc switches form the one assembly). Note: be careful when removing the control panel - the control cables must be unclipped from the back of the panel by rotating their plastic clips. They are easy to break.
4) Looked long and hard at the vent control knob and its mechanism. Observed that the vent control knob has a toothed cog that engages with another that in turn rotates a cam plate into which two sliding pins insert.
5) Realised that they two cogs are designed to stay in register with one another, and this is achieved by a rather nice change in tooth pattern on each of the cogs. When in register, the altered teeth mesh smoothly with each other. However, if register has been lost (the cogs are no longer in the correct rotational alignment with each other) the control knob makes awful sounds and doesn't rotate the other cog correctly.
6) Fix is to place the cogs back into correct register, achievable by some temporary bending of the mounts and judicious slipping of the teeth past each other until the 'altered teeth patterns' line up with each other and so both rotate smoothly through 360 degrees.
7) Final step is to use Vaseline to lubricate the cogs, the cam plates and the heater box cam plate (accessible by removing the glovebox) so that the forces acting on the heater control are not so great that teeth slippage occurs.
System now works as new.
1) Bought T5 cab chassis
2) Found vent control knob defective (the one that directs air at face, floor, etc). It wouldn't direct air and made awful 'broken' sounds as it was turned.
3) Pulled out assembly (the two knobs plus air con and recirc switches form the one assembly). Note: be careful when removing the control panel - the control cables must be unclipped from the back of the panel by rotating their plastic clips. They are easy to break.
4) Looked long and hard at the vent control knob and its mechanism. Observed that the vent control knob has a toothed cog that engages with another that in turn rotates a cam plate into which two sliding pins insert.
5) Realised that they two cogs are designed to stay in register with one another, and this is achieved by a rather nice change in tooth pattern on each of the cogs. When in register, the altered teeth mesh smoothly with each other. However, if register has been lost (the cogs are no longer in the correct rotational alignment with each other) the control knob makes awful sounds and doesn't rotate the other cog correctly.
6) Fix is to place the cogs back into correct register, achievable by some temporary bending of the mounts and judicious slipping of the teeth past each other until the 'altered teeth patterns' line up with each other and so both rotate smoothly through 360 degrees.
7) Final step is to use Vaseline to lubricate the cogs, the cam plates and the heater box cam plate (accessible by removing the glovebox) so that the forces acting on the heater control are not so great that teeth slippage occurs.
System now works as new.
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