The PTC heater is located under the inlet manifold. As it heats up, the
electrical resistance increases until it stops conducting. I don't think it
turns the relay off, that is turned on by the ignition and stays on although
no current passes through once the PTC unit is hot.
I had a problem on my car with the dashboard fuse blowing intermittently
together with the PTC fuse, so I have disabled mine by removing the PTC
fuse, and there are no ill effects.
If you man PTC as in temperature mesaurement it stands for Positive
And that means that it's a pobe with a temperature sensitive resistor
element wich changes its resistance =(higher resistance with higher
In the heater case it's logical..
Cold = low resistance = high current flowing thru resistor = enough to
contol someting (relay ?)
Warm engine = high resistance = low current thru resistor probe = blocks
Could be a loose wire to hr probe, just check that circuit ith a simple ohm
meter WITH THE ENGINE ON = rattles a bt will cause the symptom sometimes !
Good luck !
(hope this was on the right track !)
thanks folks got time to check it out today, found broken wire, the clicking
was it trying to energise the relay which it hadn't been doing in the past,
when ithe wire touched it swiched relay on and the heater, looks like it
had not been working for a while because now the heater is working it goes
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