924Board.org

[3d914]

I'm in the process of debugging some minor electrical problems also:

low beams don't come on, high-beams do. Likely the relay.
low speed & temp-driven fan don't run, A/C turns both fans on high. Relay also.

The weirdest one is that the high-beams can be flashed with the light switch OFF (as well as removed all together), car off & the key out. This can't be normal - can it?
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Gerard
74-914 2.0L Ravenna Green
87-924S 2.5L Alpine White

[Smoothie]

[3d914]

Smoothie,

Thanks for the feedback. My 924 book shows the relay for the headlights, but the early 944 chart I found didn't show one. Good to know its NOT supposed to be there.

I was hoping to find some decent schematics that would help me verify the switch condition before replacing.

A/C - I'm confused by your response, since when I pulled the A/C fan relay (#1 IIRC) and checked it with voltage across 85 & 86 the relay didn't click.
I know I've replaced the temp switch a little over a year ago - though it could still be bad. Any ideas?

Also, any thoughts on why the hi-beam switch on the steering column lights up the brights when everything is off?
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Gerard
74-914 2.0L Ravenna Green
87-924S 2.5L Alpine White

[Smoothie]

You'd have to look at an owners manual for your car to know for sure what's where, but my '82 has the "cooling fan relay" in the first position. The "air conditioner relay" I believe is behind the dash at the far right side of LHD cars, accessible by removing the glovebox.
Anyway, there's a diode on that 85-86 pull-in circuit of the relay, so make sure you have your 12v+ on 85, and ground on 86. It would also help to have an ohm-meter across 30-87 to test that switch, and then across A-B to test it, while you're applying 12v across 85-86..
Obviously the rad temp switch can be tested with an ohm-meter also. Should show infinite ohms when cool, and 0 ohms when it's heated to over its' rated temperature.

Don't happen to know why the high-beams are switching on with everything else shut off.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[968rz]

The high beam flash-to-pass thing is normal, I think all Porsche/EU cars have that function; seems silly to have lights flash when they are hid but it was cheaper I'm sure to use that switch then to tool up for a new one.

To test the fan sensor at the rad (at least on my 79) you can ground one wire (key on, engine off) and the fan should come on, if not the sensor is bad.
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Rick
79 924 coupe Petrol Blue 3spd auto (wife's DD)
93 968 coupe Amazon Green 4spd Tip (my DD)

[Paul]

All the sensor does is to provide a ground for the fan motor, so grounding the wire should make the fan run regardless of the condition of the sensor or the position of the key. Ignition on: fan runs fast, ignition off: fan runs slow.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.