Ignition switch replaced, ODO lights still on drawing power

[f4ichuck]

Hi All,

After looking for solutions, I found that my car's symptoms were part of what others have resolved by replacing the ignition switch. While replacing the switch, I noticed that the red paint covering the screws that hold the switch in place had been disturbed. It appears that the previous owner had already tried this remedy. I replaced the switch anyway since I had the new part. There was no change in behavior.

I'm hoping that somebody can recommend anything else that I may try to resolve this problem. The car is a 1999 C4 and the only lights that stay on are the ones lighting the LED displays at the bottom of the instruments (Tach, Speedo). Are there relays that may be stuck closed or could this possibly be something wrong in the instrument cluster?

Thanks for any suggestions.

-Chuck

[logray]

If I understand you correctly you remove the key and yet the LED display in your dash pod stays on?

It is normal for the LED display (ODO/OBC/MPH/etc) to stay on for a period of time after the car is off. It will turn off automatically on it's own after a period of time or if you lock the car (does yours not?).

Also if the display is off, you open the car door and turn the headlights on and then back off <or> press the odometer dial the instrument cluster LED display will come on for period of time and then turn off automatically - which is also normal.

Or are you saying the "idiot lights" below the LED display stay on? For example check engine/airbag/handbrake/etc.

Edited June 7, 2011 by logray

[RFM]

The fault is most probably in the instrument cluster itself, try with a spare one, have it repaired or buy an new one. The spare and new instrument cluster must be programmed on your car with a PIWIS diagnostic tool. Success.

[whall]

If you have the display lights themselves remaining illuminated, i. e., the odometer, temperature, trip mileage, try gently pulling out on the time setting knob and/or illumination adjusting knob. If either is stuck "in" it will keep the displays illuminated.

Bill

[wvicary]

It could also be a fault with the mechanical portion of the key tumbler. When you insert the key it engages a small rod that pushes on the electrical part of the ignition switch which turns on that circuit for the gauge cluster and radio. You can test this by removing the ignition switch from the steering lock assembly but leaving it plugged in electrically, if the system operates as designed then the fault lies within the lock assembly, if the fault stills occurs then chances are it's in the cluster or a very remote chance in the alarm/lock module.

[f4ichuck]

If I understand you correctly you remove the key and yet the LED display in your dash pod stays on?

It is normal for the LED display (ODO/OBC/MPH/etc) to stay on for a period of time after the car is off. It will turn off automatically on it's own after a period of time or if you lock the car (does yours not?).

Also if the display is off, you open the car door and turn the headlights on and then back off <or> press the odometer dial the instrument cluster LED display will come on for period of time and then turn off automatically - which is also normal.

Or are you saying the "idiot lights" below the LED display stay on? For example check engine/airbag/handbrake/etc.

Thanks for the reply. Just the ODO/MPH,etc stay on. I'd hate to take this down to the dealer to figure it out. I'll try disconnecting the ignition switch to see if the lock and check the time adjustment knob to see if it is stuck. I guess I'll have some time over the winter to tinker with it some more.

I've also been keeping my eye on eBay for a used instrument cluster. Quite a few come up, but none seem to be for my 99 C4 manual tranny. Does anybody know if there is a cross reference for which clusters can be swapped with different cars?

Thanks,

-Chuck

[whall]

Chuck,

Because of the fact that you own a pre-MY02, 6-speed C4, your choices for a replacement instrument cluster are few.

The primary Part Number is:

996.641.113.03.70C ....... instrument cluster, complete .... (USA) ,,,, -01 ... M339, M480 ... Where 70C = rally black dial face, (USA) = speedometer in miles per hour/temperatures in fahrenheit, -01 = up through MY01, M339 = 4 wheel drive, M480 = 6 speed trans.

A secondary Part Number might be:

996.641.982.40. (Followed with a three digit code such as C53 graphite grey, inticating a dial color other than the standard black.)

996.641.982.40.C53 ....... instrument cluster, complete .... (USA) ..... 01 ... M339, M480 ... Where C53 = graphite grey dial face, (USA) = speedometer in miles per hour/temperatures in fahrenheit, 01 = MY01, M339 = 4 wheel drive, M480 = 6 speed trans.

There are 8 different optional dial face color instrument clusters listed in the Porsche parts catalog. And, note these instrument clusters are "intended" for replacement in MY01 cars. I think that MY01 may have been the first year that dial faces were offered in a color other than rally black. They should operationally compatable with a MY99 car.

Instrument clusters that aren't compatable with your car would any that came from a C2 or any Turbo. The C2 has a different fuel tank than a C4 so fuel quantity cannot be measured correctly. And the Turbo has a different oil quantity measuring system,so there would ba a problem there.

Also be careful purchasing an instrumant cluster from an on-line auction service. My first questin is always "WHY". Why is a seller offering a completely operational, and I might add expensive, instrument cluster for sale? Was it replaced by another equally expensive instrument cluster? Odds are that the item for sale will be a disappointment. I feel that your chances of getting a fully functional instrument cluster are better dealing with a breaking yard. The used instrument cluster was more than likely operating properly when the donor car was wrecked.

Bill

[logray]

...Just the ODO/MPH,etc stay on...

How long does it stay on?

[f4ichuck]

They stay on indefinitely. Basically until the battery goes dead or I disconnect it.

-Chuck