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986 2.7 2000 - No interior lights or electric windows


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Any thought on what might be causing this issue?

Got no interior cabin light, no power to the windows and no boot / trunk light either.

Also weirdly I can tilt the electric side mirrors up and down but not left and right.

Everything else seems fine, fan, heater, all external lights, horn, wipers all working as normal.

Fuse C3 (15a) is a combined jobbie that is for the alarm control module, power windows and interior lights so I thought that might have blown , but it's fine,  I even swapped it just in case but no joy.

Any thoughts most appreciated!

Thanks!

Edited by joeluth
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Consider Richard H's advice first (he knows more about these things than I ever will) but another thought it might be an ignition switch issue. They are known to wear and cause varied electrical issues. 

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5 minutes ago, Boxob said:

Consider Richard H's advice first (he knows more about these things than I ever will) but another thought it might be an ignition switch issue. They are known to wear and cause varied electrical issues. 

Good call. Definitely worth trying, and not expensive. 

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Does the alarm arm (and LED flash) and disarm (doors + boot/frunk unlock) okay? Interior lights and windows are controlled by the alarm unit. I had similar symptoms when my alarm hadn't unlocked properly.

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I also changed the ignition switch - good to rule this one out when diagnosing electrical issues and they're cheap enough. You can change it yourself with a little hoking around under the dash.

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21 hours ago, Kay Pee said:

Does the alarm arm (and LED flash) and disarm (doors + boot/frunk unlock) okay? Interior lights and windows are controlled by the alarm unit. I had similar symptoms when my alarm hadn't unlocked properly.

Thanks Kay. I did install a new ignition switch, nothing changed,  but I found water damage to the alarm unit under the passenger seat : (     trying to get a replacement. What a mare.    No central locking, or frunk.. rear trunk still unlocks. 

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1 hour ago, joeluth said:

Thanks Kay. I did install a new ignition switch, nothing changed,  but I found water damage to the alarm unit under the passenger seat : (     trying to get a replacement. What a mare.    No central locking, or frunk.. rear trunk still unlocks. 

I was going to suggest that this is likely your problem. 

AFAIK, you will need to replace the immobiliser, ECU and transponder chip as a set.

Breakers sell them as a kit.

Simple job to switch over but you may run into problems with PIWIS etc in the future and key coding as an example. 

Rich Hamilton can advise more on this. 

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1 hour ago, TROOPER88 said:

I was going to suggest that this is likely your problem. 

AFAIK, you will need to replace the immobiliser, ECU and transponder chip as a set.

Breakers sell them as a kit.

Simple job to switch over but you may run into problems with PIWIS etc in the future and key coding as an example. 

Rich Hamilton can advise more on this. 

That's absolutely correct, and you need to find a set from exactly the same model.  Yes, once you do it you will have trouble getting another key coded to the car.

Personally, I would bite the bullet and get a new alarm control module, and have it properly coded to the car.  The module is about £450, which is about what people charge for a matched set of DME, ACU and keys.

Alternatively, have a word with JMG Porsche.  I believe they have facilities for reading out the EEPROM on your existing unit, and transferring it to a good used unit.

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5 minutes ago, Richard Hamilton said:

That's absolutely correct, and you need to find a set from exactly the same model.  Yes, once you do it you will have trouble getting another key coded to the car.

Personally, I would bite the bullet and get a new alarm control module, and have it properly coded to the car.  The module is about £450, which is about what people charge for a matched set of DME, ACU and keys.

Alternatively, have a word with JMG Porsche.  I believe they have facilities for reading out the EEPROM on your existing unit, and transferring it to a good used unit.

Alternatively, I do believe that some have been successful in opening up wet immobiliser units and drying them out.

 

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4 hours ago, TROOPER88 said:

Alternatively, I do believe that some have been successful in opening up wet immobiliser units and drying them out.

 

This maybe, depends on the amount corrosion.  I was hugely lucky that the water damage on mine was limited to a single circuit, interior light and vanity lights in the sun visors, which had happened before I owned the car.  Found the fault it eventually and traced it tot eh alarm module  and bypassed it with help of @Richard Hamilton and him providing some very helpful circuit diagrams.  I applied lots of contact cleaner along with carefully brushing the circuit board and left in a warn dry place for 36 hours to ensure it was dry and I now regularly make sure the car is dry.

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22 hours ago, ½cwt said:

This maybe, depends on the amount corrosion.  I was hugely lucky that the water damage on mine was limited to a single circuit, interior light and vanity lights in the sun visors, which had happened before I owned the car.  Found the fault it eventually and traced it tot eh alarm module  and bypassed it with help of @Richard Hamilton and him providing some very helpful circuit diagrams.  I applied lots of contact cleaner along with carefully brushing the circuit board and left in a warn dry place for 36 hours to ensure it was dry and I now regularly make sure the car is dry.

Really appreciate all the feedback on this,  I've attached a few photos, here's what the unit under the passenger seat looked like when I found it.

I've since brushed away the worst of it with a paintbrush and re-installed it however the situation hasn't changed. 

I think it's a bit too far gone for a contact cleaning session, but maybe I'll give that a go just to see if anything comes back to life, thing is I don't want to make it worse,

@Richard HamiltonI've taken your advise there and booked it in for a replacement unit and programming,  everyone is so busy though, found a place not too far from me and they squeezed me in for the 10th June.

 

 

 

ECU03.JPG

ECU02.JPG

ECU01.JPG

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Looks like a lot of corrosion damage around the two chips and capacitors over the NEC boxes. ☹️

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yeah, it's looking pretty sorry for itself, I'm going to take it out and clean it up best I can, hopefully I'll get it to behave a bit better whilst I'm waiting for  replacement.

Would you be able to share those diagrams with me? I'd really appreciate it if you could! 

 

On 5/1/2021 at 11:10 PM, ½cwt said:

Looks like a lot of corrosion damage around the two chips and capacitors over the NEC boxes. ☹️

 

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Posted (edited)

Thanks again, after having a good look at the board with a magnifier  I think it's too far gone for me fix myself!   

I found this company on-line, they do a specific 986 alarm module repair service for £350 

Has anyone dealt with such a service or company before?    I didn't think a repair was an option, rather that it would need replacing and coding.

https://motortronics.co.uk/product/porsche-986-alarm-module/

 

Edited by joeluth
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