Mk2 heater control switch controlling power to radio & voltmeter

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Judy
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Mk2 heater control switch controlling power to radio & voltmeter

Post by Judy » Tue Aug 14, 2018 2:32 pm

1989 1.8i scala, my voltmeter and radio only work when the fan heater switch is in either setting 1, 2 or 3 there is no power to either when the switch is positioned to 0.
The heater blower itself is noisy, I've vacuumed it out and tried some wd40 but it still doesn't spin freely so I've ordered a replacement off ebay. I think that's probably unrelated but I thought I'd mention it just in case.
I've also noticed the lights on warning beeper only works with the heater fan turned off.
Is there a common circuit or earth here that could be causing this?
I would welcome any suggestions anyone has on possible areas to check.
Thank you
Judy



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unknownmale
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Re: Mk2 heater control switch controlling power to radio & voltmeter

Post by unknownmale » Tue Aug 14, 2018 5:23 pm

Sounds like someone wired your radio and Voltmeter power to the output of your switch. Have a look behind the radio, might be a loose power wire possibly arching about. If not. Run a fresh switched power from the fuse box.

In my experience across a few brands once the blower motor starts complaining it has a rusty shaft and is on it's way out. I've tried repairing a few, but not worth it for the price of a replacement in my opinion.

If you have a beeper on when your lights are on then it's an aftermarket add on. Usually wired to the headlight switch to the door switch.

Sounds like the previous owner liked playing around with the electrics!

My suggestions;

1. Check for any loose wires behind the radio
2. Run a new switched power to the radio and distribute to the voltmetre
3. Remove any bare wires coming from the heater switch. The circuit isn't rated to have all this stuff run off it so you're likely overloading it. You may blow the fuse for this circuit.
4. Check the previous owner hasn't put a higher rated fuse in its place to stop this happening. The gauge of the wires in the circuit determine the max current, not the fuse!
5. Remove that door buzzer.

Hope that helps


- David

Judy
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Re: Mk2 heater control switch controlling power to radio & voltmeter

Post by Judy » Tue Aug 14, 2018 5:44 pm

Thanks David, the beeper is when the lights are on and the fan is off, V unsure about it, didn't seem right but is coming from the depths of the under dash so was assuming it's original. Are there any other warning beepers on the car?
When I can find the gadget for getting the radio out that's exactly what I'm going to do, just seems odd, the rest of the car is immaculate so it seems odd he would do a bodge like this.
Seems like there is going to be some hanging upside down under a dash board coming up :(



moser
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Re: Mk2 heater control switch controlling power to radio & voltmeter

Post by moser » Tue Aug 14, 2018 6:01 pm

Its quite common for the switched live for the radio to be taken from the blower switch. I believe its the black and yellow wire


91 Scirocco Scala - Too low for MOT ramps apparently
03 Seat Cordoba PD130 - Daily
52 Golf 1.6 - Mrs' shopping trolley

Judy
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Re: Mk2 heater control switch controlling power to radio & voltmeter

Post by Judy » Tue Aug 14, 2018 6:12 pm

Okay thanks, I'll do some more investigation on that wire in the morning.