Monday, Oct 07, 2013 at 12:12
I had a new EA Falcon Ghia in 1990 with Climate Control. Dial up the temperature and the microprocessor in the dash and about a dozen sensors keep it all at the set temperature.
The CC stopped working at 19500kms, just inside warranty. Took it into the Ford dealer and the service manager told me about how fantastic all this new electronic technology was.
All I had to do, he said, was press a number of the control buttons on the CC control panel, simultaneously and in the right sequence - and the fabulous and clever little microprocessor changed from controlling the temperature in the cabin, to a diagnostic tool!
Once the
test sequence buttons were pressed, the MP divided the circuitry up into 10 separate sections, tested each one for a fault, found the fault, and produced the fault code on the screen!
"Great!", says I, "let me see it in action!" So the manager presses all the buttons simultaneously in correct sequence - and the dash screen comes up with - "No Error".
I said - "That can't be right. The CC isn't working, it's that simple! There's a fault in there somewhere".
The SM was crestfallen and admitted he'd have to put the car into the
shop and do further testing. 4 hours later, when I return, he says, "We found the fault! It was a dirty fuse on the A/C compressor!"
"Great!", I said - "But why didn't the MP find it?" He shrugged and said he couldn't understand why it didn't - it might have been because it was an intermittent fault that wasn't there when the MP went into self-
test mode.
I took the car away. Another 4 hrs later, the CC stops working again. Pressed the buttons on the dash - "No Error" was still the message. Back to the Ford dealer, and more head scratching. Into the
shop, for more intensive fault-finding.
Next day I get a call, it's right to go.
When I pick it up, I say to the SM, "What did you find wrong?". He says, "the microprocessor in the dash had totally failed!
The microprocessor can find faults in the system - but it can't tell you when it has failed itself!"
Then came the kicker - "Geez, it's lucky you got this new MP under warranty! They're $940 list price as a part! (this was 1990, remember, when the AU$ bought more).
"And you know, as I do", I said - "that there's a total of $25 worth of silicon chips in there!"
"Yeah, you're probably right", he says. "What I do know, is that the MP is unrepairable. We had another one pack up a few months ago, and the car belonged to an electrical engineer. He asked for the old MP to see if he could figure out how it worked, and how it was built, and if he could fix it.
He came back a fortnight later and said he'd opened it up, had basically figured it all out - but there was a silicon chip control unit in the middle of it, that was stamped 'VDO' - and VDO would give him no info on what was in that control unit - and it was not available as a separate part!"
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