[WYLDCTZ]

Just thought I'd add to the history on the new site with info on my favorite 968 mod: Making your convertible top work even when the engine is running.



This was originally devised by memartin on 968.net, so I thought I'd give him his props...



How to bypass the dumbest idiot proofing ever on a car:

First, open your hood and find the fuse box. It is located pretty close to the windshield on the drivers side.

Find the G21 relay. (large square black fuse thingy)

Pull it out and find pin 6. This pin needs to be covered or disconnected somehow for your cab top to open and close with the engine on. Some people found that if they wrapped it in black electrical tape and reinserted the relay, that this worked. I personally could not get the tape to stay on when I reinserted the relay, so I just bent pin 6 to the side and put the relay back in. If I ever want to switch it back, I can just bend the pin back straight.



Some people actually have cut off the pin completely, but if you do that, then you have to replace the entire relay if you want to revert back to the stock configuration.



Thats all there is to it. Enjoy.



Mark (WYLDCTZ)



Here is some techy info posted by Techguy I found on how this all works...



----

The electrical system is composed of the fallowing components:

1.(2) roof actuation motors

2. A control relay for each of those motors

3.(4)limit switches (microswitchs)

4. Operation switch (center console)

5. Relay G21



A hard wire logic is established by the interconnection of the limit switches and the electric motor control relays. The limit switches detect the fallowing conditions:

1. Roof closed position

2. Roof open position

3. Roof locked

For example, if the roof is locked, actuation motors do not operate.



Relay G21 is the main control in this system. It is not a conventional relay with an inductive coil, this is a solid state relay (we can say it could be a small "ecu"). G21 decides if the roof can be actuated or not by means of a voltage (current) supply wire to the roof operation switch in the center console. G21 have the fallowing input signals:

1. Switched 12V+ (ignition switch)

2. Battery 12V+

3. Speedometer Signal

4. Ground (12V-)

5. 12V+ from the Fuel pump voltage supply line.



The logic programmed inside G21 is unknown. But based on what Bruce explain, when the engine is turned on G21 activate (enable) an interlock that prevents the roof to operate. Remember that a 12V feedback signal is received by G21 from the fuel pump. Taking the ignition switch to the off position must reset this interlock.

----

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[Guest]

I have only been on the 968.net for about a year and never saw this posted there. I am so psyched. The top system was a real pain, can't wait till it warms up in NY to try this out.

Thanks

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[BigL2U]

Thanks WYLDCTZ (and memartin).. That was one of the most annoying aspects of the top for me when I first bought this car. I'm having a new top put on next month and removing pin 6 of G21 will be the first mod I make after that.. <img src="/forum/images/smilies/968/tongue.gif" class="smilie" alt="" />

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[Mark]

This was definitely the best mod ever for the cabs and was a very popular thread on 968.net for quite a while..

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[top_gun92]

[quote name='daly' date='Feb 2 2005, 09:01 PM']I have only been on the 968.net for about a year and never saw this posted there. I am so psyched. The top system was a real pain, can't wait till it warms up in NY to try this out.

Thanks

[right][post="127"]<{POST_SNAPBACK}>[/post][/right][/quote]



where at in NY?

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[Ryan]

I see where there is a roof closed position when the motors won't work. Flash said he blew a fuse trying to open his top while it was latched. How can this happen unless there is something out of kilter?



I did this mod last year. Great, but the top will not go down while I am backing out of my parking spot. Is there a motion detector? I wonder if it can be bypassed?

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[flash]

not sure how it happened - frankly haven't tried to recreate the scenario and have quite happy it just works - everything seems to be adjusted correctly - the gap is gcorrect - everything is even - both motors are quiet and smooth (knocking on wood now) - i'm more than a little nervous about trying to recreate the failure - all i know is it worked going down and back up just fine - then i failed to pop the top loose from the header rail, heard the motor for a second, then dead - fuse blown - popped the header loose, changed the fuse - all is well



as for putting it down while moving, this is a VERY bad idea - the alignment and speed synchronization of the motors is precarious at best - adding wind resistance or gravity interjection due to movement is asking for a failure - as cool as it might be to be able to do that, and it is possible in other cars, this one is a bad design and fragile - i would seriously rethink that



another thing, while i have made the mod, and intend to take occasional advantage of being able to put the top down without getting out of the car, it will not be a regular practice for the following 2 reasons:



1. i intend to use the boot cover almost every time to protect the headliner from getting dust embedded in it and to keep it from fading



2. i put a towel over the plastic back window before putting the top down - this prevents the window from creasing, scuffing and getting hurt - my window is orignal and still looks perfect for that very reason



something to think about

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[sayporsha]

Right on! With all of the sophisticated drop-while-you-drive tops out there these days, I felt like my 968 was from the dark ages. I don't intend to raise/lower it while in motion, but at least I don't have to shut the bloody thing off if it starts raining at a stop light!



Thanks for sharing this.

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[flash]

yeah - not sure what they were thinking there - with a base mustang having a heated glass rear window and full power, i don't understand why porsche stuck with what they did - any what's the deal with it sticking up so far? complete screw up

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[daly]

[quote name='top_gun92' date='Feb 2 2005, 02:20 PM']where at in NY?

[right][post="130"]<{POST_SNAPBACK}>[/post][/right][/quote]





Queens NY

Douglaston

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[daly]

[quote name='WYLDCTZ' date='Feb 1 2005, 04:54 PM']Just thought I'd add to the history on the new site with info on my favorite 968 mod: Making your convertible top work even when the engine is running.



This was originally devised by memartin on 968.net, so I thought I'd give him his props...



How to bypass the dumbest idiot proofing ever on a car:

First, open your hood and find the fuse box. It is located pretty close to the windshield on the drivers side.

Find the G21 relay. (large square black fuse thingy)

Pull it out and find pin 6. This pin needs to be covered or disconnected somehow for your cab top to open and close with the engine on. Some people found that if they wrapped it in black electrical tape and reinserted the relay, that this worked. I personally could not get the tape to stay on when I reinserted the relay, so I just bent pin 6 to the side and put the relay back in. If I ever want to switch it back, I can just bend the pin back straight.



Some people actually have cut off the pin completely, but if you do that, then you have to replace the entire relay if you want to revert back to the stock configuration.



Thats all there is to it. Enjoy.



Mark (WYLDCTZ)



Here is some techy info posted by Techguy I found on how this all works...



----

The electrical system is composed of the fallowing components:

1.(2) roof actuation motors

2. A control relay for each of those motors

3.(4)limit switches (microswitchs)

4. Operation switch (center console)

5. Relay G21



A hard wire logic is established by the interconnection of the limit switches and the electric motor control relays. The limit switches detect the fallowing conditions:

1. Roof closed position

2. Roof open position

3. Roof locked

For example, if the roof is locked, actuation motors do not operate.



Relay G21 is the main control in this system. It is not a conventional relay with an inductive coil, this is a solid state relay (we can say it could be a small "ecu"). G21 decides if the roof can be actuated or not by means of a voltage (current) supply wire to the roof operation switch in the center console. G21 have the fallowing input signals:

1. Switched 12V+ (ignition switch)

2. Battery 12V+

3. Speedometer Signal

4. Ground (12V-)

5. 12V+ from the Fuel pump voltage supply line.



The logic programmed inside G21 is unknown. But based on what Bruce explain, when the engine is turned on G21 activate (enable) an interlock that prevents the roof to operate. Remember that a 12V feedback signal is received by G21 from the fuel pump. Taking the ignition switch to the off position must reset this interlock.

----

[right][post="67"]<{POST_SNAPBACK}>[/post][/right][/quote]





Does this disable the hand brake safety garbage also, you know hand barke on to move the top>

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[KensCab]

I did the tape on the pin trick, took a couple of trys to get it isolated but it does work great. Never did like the have to pull over, stop, turn it off, top up or down thing, restart the car... what a pain in the posterior, this IS great !!!!

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[flash]

it is a very cool mod, and when i put the top back in power mode next week, i will possibly use it



i think my next thing is to trim down a towel so it just covers the back window, thereby making that step of the process easier - it tends to want to move if there is any breeze, and that towel is the only thing keeping my back window from showing any signs of wear

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[KensCab]

[quote name='flash' date='Feb 11 2005, 08:28 PM']it is a very cool mod, and when i put the top back in power mode next week, i will possibly use it



i think my next thing is to trim down a towel so it just covers the back window, thereby making that step of the process easier - it tends to want to move if there is any breeze, and that towel is the only thing keeping my back window from showing any signs of wear

[right][post="606"]<{POST_SNAPBACK}>[/post][/right][/quote]



Flash--- I realatively new to these Cab's, when in the "manual" mode of the top is it stiff or difficult for one person to pull it up or push it down?

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[Anchorman]

In "manual", the top is quite easy to put down, and only slightly more difficult to put up. You can put it down without leaving the driver's seat (I don't worry about the "towel on the window"). To put it up, you have to get out of the car, but it's easily done from one side. Other than the inconvenience of having to get out to put it up, I find manual to be faster (and safer) than power. I have no intention of ever going back to power operation (at least not until I'm ready to sell).

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[KensCab]

Thanks, this sounds like a great way to maybe eliminate another thing that could go wrong. I've heard some horror stories about the frame work bows breaking, cable syncronizing etc.

Is it a bunch of trouble to disengage the power to the top?

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[Anchorman]

To put the top in "manual", you have to remove the two plastic caps that are on the side walls of the rear compartment. Loosen the two nuts (same size as lug nuts). Replace caps. Done. Instructions are also in your owner's manual.

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[KensCab]

Thanks, I did get the owners manual and found that.

I quess I should just looked before asking.

But, thanks again...

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[Anchorman]

Not to worry. Your asking gets the information out there. Not everyone has an owner's manual.

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[earossi]

Speaking of cab roof mods, are there any preventative maintenance steps that can be taken to prolong the life and operation of the top mechanism? Also, in a prior post, the comment was made that if one of the actuating cables snaps, you'll break a top bow. Does this impending disaster give any warning? Also, if you do manage to break a bow, where can you get a replacement part?



I guess that what I am asking is for info on PM that will keep my cab top mechanism working properly for years to come.



Thanks.

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