924Board.org

[alxch1n15]

Hey all,
so when i drive my car, 924 n/a '81, after 5 or 6 minutes its supposed to warm up and that will be shown by the temp. guage on the dash. but instead of it working like on every other car, it doesnt... being somewhat new to porsches, i dont know where the problem would originate from. the car does get heat though, and after a few minutes of driving will produce heat from the vents. note: there is no response from the meter on the dash, it will flick and move some when the car is first started up, but after that immediate surge of power, it lays still.
any help with this would be great,
alex

[Lizard]

most likely the wire is not on the temp sensor (back of head), or the sensor has become faulty.
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3 928s,

[alxch1n15]

whats the best way to access the rear side of the instrument?

[ideola]

You should check the temp sensor first because there is a multi-pin connector on the back of the combo gauge. Chances are, everything is fine at the gauge side.

In any event, to answer your question:
In order to access the rear side of the instrument cluster that has the temp meter, battery light, fuel guage, etc. you have to press out all three instruments. You might be able to get to just the combo gauge itself, but it's easier to press out all three because there's not enough slack in the wiring harness to get the combo gauge completely out with the other two still in. At lease that's the way it is on mine.

Do NOT remove the two screws that hold the gauge bezel in place. You don't need to remove the bezel in order to remove the gauges. Also, be careful with the rubber strap that surrounds each of the gauges. This is what holds the gauge in place. The rubber may have started to split from age, and you don't want it to break or your gauges won't fit firmly into the bezel when you put them back.

Start with the tach. Get a flash light, and stick your head under the dash with your feet on the back of the driver's seat. Reach up with your hand past the hazard and defog switches and apply firm even pressure to the back of the tach. It will be stiff, but you should be able to push it out. While you're down there, you should think about cleaning ground crowns that are above the fuse block.

With the tach pushed out, and back in a seated position, label and remove the wires and set the tach aside. Then reach your hand thru the gauge bezel opening where the tach was, and press the speedo out part way until you can get ahold of the speedo cable. Unscrew it, and press out the speedo. Label the wires and remove them.

Reach thru the gauge bezel opening where the speedo was and press out the combo gauge. There is a multipin connector at the top which provides all of the connections for the combo gauge.

While you have all of your gauges out, replace the small lightbulbs with the brighter replacement Sylvania 2723 bulbs. These will improve (somewhat) the brightness of the' backlighting' for your main instrument cluster at night when your lights are on. You will need a minimum of six, eleven if you want to replace all of them.

There are two each on the tach and speedo. On the combo gauge, there is a total of seven bulbs if you feel industrious, but you should only need to replace the top and bottom ones which provide 'backlighting'; the other small bulbs in the combo gauge don't provide backlighting and probably are OK. Plus, the bulbs in the lamp holders in the combo gauge are *soldered* in, so they're a PITA to replace.

Have fun!
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erstwhile owner of just about every 924 variant ever made

[augidog]

Lizard is right,
check the sending unit behind the head toward the passenger compartment.
I had the same problem and it was a loose wire to this unit. If your getting a spike ,probally the ground is off its pin.
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

[Mannghi]

I had the same problem, it was loose wires to the sending unit. It's easy to get at (easier than some things anyway). I'd check there first. Going behind the dash as a last resort.

[alxch1n15]

thanks guys, when i get my garage cleaned out it will be looked at
alex

[alxch1n15]

hey everyone, sorry for the delay on this post, ive been trying to obtain a haynes to get to know the engine a little better. what does the sending unit look like?
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'81 924 n/a

[CMXXXI]

See if these will help you...
..
Click photos for larger images
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'79 Eurospec 931

[alxch1n15]

thanks, those helped a lot
if it werent hovering around 0 degree's i'd go out and take care of it, hopefully we'll have a warmer next few days here in wisconsin
alex
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'81 924 n/a