HCV Control Volt Check

[Pkp]

Brain was wandering (as it does at my age) and I was wondering how to check the square wave that controls the HCV without an oscilloscope.

Has anyone tried connecting a 12v bulb to the plug and seeing if the brilliance varies as the control is moved up and down from hot to cold? As the pulse width is varied it should vary the brilliance from very dull at hot and bright for cold.

 

[red]

I haven't heard of anyone trying to test it. Same part across a few Fords I think so someone probably has I imagine.

 

[zinc2000]

10.17 at night and your brain is working on that!! my brain is already in hot chocolate and bed mode by then :grin:

but thought did occur to me.....why?

 

[Ian G]

Pulse width is indeed visible with a bulb and the helpful chaps at Ford have given it the same plug as a driver's indicator side repeater so you've even a ready made bulb holder available to plug straight in.

You won't see brilliance as the pulses are very slow - <1Hz - very easy to see by eye as its either on or off for a few seconds or so (or solid in the case of either end of the scale)

 

[Ian G]

[post]360958[/post] I haven't heard of anyone trying to test it.

Its easy to do and good information to spread about if anyone asks - will diagnose the panel prior to any major strip down. Preferable to people spending money on a valve and fitting it to find out the panel is faulty.

 

[Pkp]

Thanks Ian, I shall have a look myself on a sunny day after I have done all the gardening. My experience of Pulse Width Modulation is at much higher frequencies.

As to why I was thinking about it at that time of night, just put it down to being an engineer, (and according to my wife all engineers are weird, but useful) and personality problems picked up whilst serving in submarines!