G25 to G27 and Vice Versa Shifter

OK many have asked and just about everywhere people say NO, so I did some tinkering as I upgraded from my second hand G25 to a new G27 (isn't ebay great) and I say YES.

Explanation:-

While the G25 to G27 Shifter Units are not directly compatible ie Plug into each other the method of making it so is so bloody simple it's laughable.

Logitech must think all us racer's are rather stupid. I started investigating this since pots were not available from Logitec and I have since found a suitable replacements.

Now apart from the obvious sequential mechanism components the electronics of the G25 and G27 Shift units are Electrically IDENTICAL in fact even if you don't have the mechanism from an old G25 shifter, simply by drilling one hole for the LED and soldering in a toggle switch to turn the LED on and switch the chip from 3rd and 4th to 1st and 2nd as shown on the Calibration GUI in Windows then you G27 Shift has morphed into a G25. You will however need to slip in a couple of springs or similar to give you return to centre.

To get your Standard G25 Shifter working as part of your G27 System all you need to do is a VERY basic rewire of the DB9 Socket on the Shifter Cable.

As shown in the diagram below the G25 Plug is wired ever so slightly different with a jumper linking Pin 9 to Pin 1 and a Purple wire on Pin 7

Where as the G27 has Pins 9 and 7 linked with the purple wire moved to Pin 1 .

To make the G25 Shifter compatible with the G27 Wheel you remove the wire link from Pin 1 and solder it to Pin 7, linking Pins 9 and 7

The Purple wire currently on Pin 7 gets soldered to Pin 1.

Thats it your done.

See the image below.





If you want your G25 Shifter to work with the G27 Wheel you wire your G25 Shifter Cable as indicated in the bottom G27 Diagram.

If you want your G27 Shifter to work with the G25 Wheel then re-wire the Plug on the G27 Shifter Cable as per the G25 Diagram.

PLEASE bare in mind the Colour substitution difference between the G25 and G27
Pin 5 G27 White = G25 Red
Pin 9 G27 Red = G25 Black
ALL other wire colours are identical and go to the exact same pins inside the Shifters.

If it truly is that simple.. Amazing, thanks for the info! 👍

That's a nice find/mod. I'm sure it'll be a big help to many on here 👍

Edited this post and included it in the one above

MozzMann

I started investigating this since pots were not available from Logitec and I have since found a suitable replacements.


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Hi Mozzmann, can you tell us where to find these suitable replacements?

MozzMann

To get your G25 Shifter working as part of your G27 System all you need to do is a VERY basic rewire of the DB9 Socket on the Shifter Cable.


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Sorry, this might be a silly question but the DB9 socket on the cable is hard plastic. How do you dismantle it? Do you cut it open or is there a trick to removing it?

itrdc5

Hi Mozzmann, can you tell us where to find these suitable replacements?

Sorry, this might be a silly question but the DB9 socket on the cable is hard plastic. How do you dismantle it? Do you cut it open or is there a trick to removing it?

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I found the Pots used in the Saitek Throttle quadrant a very similar unit. but they do need some mod's to work properly, I am obtaining some from Frex also as these are so close to the Logitech ones it aint funny.
The Pots in the Pedals are a standard Audio Taper 10K 300 Deg Rot Pot, essentially ANY 10K pot will do depending on the mounting clearance
I replaced mine and with a tiny bit or mucking about they work a treat so the Kids G25 has a new leas of life.

Not a silly Q at all, The DB9 socket that plugs into the wheel is simply cut of and a New one soldered in it's place. Depending on where you are in the world it can be got from Fry's , Tandy, Dick Smith, Radio Shack and I suspect the average Computer store may well have them.

MozzMann

Not a silly Q at all, The DB9 socket that plugs into the wheel is simply cut of and a New one soldered in it's place. Depending on where you are in the world it can be got from Fry's , Tandy, Dick Smith, Radio Shack and I suspect the average Computer store may well have them.

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Thanks so much for the reply and for posting this topic.

Well, I cut down the socket with a pen knife...boy, it took a while. I was just checking to make sure your diagram was correct...and yes it was spot on .
I got my new DB9 socket and enclosure (might be a bit big to fit in the wheel) from JayCar and I'm ready to solder it.



Oh...have to go watch Smurfs movie with the kids now so will do that later. I'll report back when done.

Mate if needed you could just pot the back of the DB9 with epoxy.

MozzMann

Mate if needed you could just pot the back of the DB9 with epoxy.

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I don't have any epoxy, but I have a hacksaw, so I just sawed off part of the enclosure



Testing the G25 shifter with G27 wheel. Everything works, now I have a spare shifter. Thanks!

My heated discussion with one chap over this working have now been vindicated.

I might have trimmed the Cable locator rather than the DB9 Backshell

anyways thanks Sir.

Cool. Ordered a replacement g27 shifter for my g25, and thought it would just plug in and work. Guess I'm off to Radio Shack now. Thanks for the post. If you need a replacement shifter.

http://www.ebay.com/itm/Logitech-G2...397?pt=LH_DefaultDomain_0&hash=item415f444325

Help here. I'm trying to solder this thing up. What exactly is blk/shld? That bare copper wire needs to be soldered with the black or something? What is it's purpose. and I have to make my own jumper?

Nevermind hahah. I works!!!!!! I love it!!!! I had it completely backwards the first time I soldered it. Woot!!!! I'm so happy..

Okay I am stumped I need some advice. I rewired my G25 shifter and everything works except when I up shift sequentially, I can go down and up but I can't go past 2nd gear. Shifting H gate style is fine.



Also if I shift up with the paddles and then try to upshift again, say from 4th to 5th it goes right back to 2nd gear, if I am in 1st and upshift it will go to 2nd. Surely if I missed something up there would be other things not working besides just that right.

trk29

Okay I am stumped I need some advice. I rewired my G25 shifter and everything works except when I up shift sequentially, I can go down and up but I can't go past 2nd gear. Shifting H gate style is fine.



Also if I shift up with the paddles and then try to upshift again, say from 4th to 5th it goes right back to 2nd gear, if I am in 1st and upshift it will go to 2nd. Surely if I missed something up there would be other things not working besides just that right.

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Not sure if this helps but I realised my wiring is slightly different to the one in the original diagram? My red wire is where the white (5) is showing and blk/shield (6) in the diagram I have white/shield. Well, maybe there are different versions of the G25 shifter but my 'shield' wire was white once you stripped off the shield bit.

Included images of my wiring, yes, I know I cannot solder but hey it works.



Good luck. Let us know how you go.

Thanks for posting the pics and taking the time to label everything. No need to send them to my e-mail.

Yeah my wires are the same blk/shield was white/shield and that is what was confusing. After seeing your socket I wired mine up correctly! I also had a buddy at work a E&I check out the pots and he said they were working up to the board. So if my shifter doesn't shift past second in sequential then I don't know what else could be the problem unless it is the board, and I don't know if I could even get another board from Logitech... I doubt it. I don't see how my shifter would shift H gate but not sequential, mechanism is all in tact. Oh well I will find out tonight if it works or not.

I will post pics of my completed socket when I get home. Nice soldering by the way that crap is hard. I was soldering the wires into the push pins then inserted them into the socket using (I think) #44 solder, almost as thin as the wire had to use a 7X magnification glass.

Well rewired the socket and the pots tested okay. I don't really know what else the problem could be. H pattern shifting through all gears but I can not shift past 2nd gear in sequential mode. ARggggghhh anybody?

If the board is bad would I be able to shift H style?

EDIT: I reversed the shifting in the menu making sequential back (down gear) and forward for (up gear) when I press forward it won't shift past 1st, if I paddle shift to a higher gear and then pull back to downshift it goes to first. It looks like only 1st and 2nd gears are the only available gears while sequential shifting which doesn't make any sense. Sequential works going from 1st to 2nd then back to 1st .

Sounds like its not actually doing sequential at all but it is seeing that as a gear position.


What happens when you switch to sequential mode is that turning the knob closes a switch that makes it recognize shifter movement as +/- instead of a gear position. Now the same pot that would be recognizing if you moved the shifter into one of the front gates or top gates is seeing if you're pulling back or pushing forward. I don't understand why it only works once each way, basically.

Eric.

Sounds like its not actually doing sequential at all but it is seeing that as a gear position.


What happens when you switch to sequential mode is that turning the knob closes a switch that makes it recognize shifter movement as +/- instead of a gear position. Now the same pot that would be recognizing if you moved the shifter into one of the front gates or top gates is seeing if you're pulling back or pushing forward. I don't understand why it only works once each way, basically.

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I wish I knew why it works in H gate and not sequential mode. If the pot was bad then it wouldn't work H gate either right?

Okay I just finished taking apart my G25 shifter again. I hooked a meter to the pot and to the end of the plug until i found the right pin. I placed the shifter into sequential mode and watched the numbers change as I pulled the stick back and the meter was showing a change. I have no clue..... Still doing the same thing.

Anybody?

Yeah the up/down pot is used for sequential and H-gate.

trk29

Okay I just finished taking apart my G25 shifter again. I hooked a meter to the pot and to the end of the plug until i found the right pin. I placed the shifter into sequential mode and watched the numbers change as I pulled the stick back and the meter was showing a change. I have no clue..... Still doing the same thing.

Anybody?

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Well the only time I ever seen that was when playing pc racing games, havin set both 1-6 and up + down gears it goes from 1st to 2nd and back, thats all.

I guess your playing GT5? if so i have no idea what would cause it

liquid07

Well the only time I ever seen that was when playing pc racing games, havin set both 1-6 and up + down gears it goes from 1st to 2nd and back, thats all.

I guess your playing GT5? if so i have no idea what would cause it

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Yes that is correct I am playing GT 5 H pattern works fine but sequential still only shifts from 1st to 2nd.
I also wonder if deleting my save data and use my back up per 2.02
I didn't even think to try another game, I will try that this evening.

With what you saw with your pc game is the same thing?

Any joy getting it to work trk?
What I ment was sequential only shifting to 2nd and back to 1st (same problem you have) when the gears are assigned to H shifter and also sequential at the same time on PC games (not possible to assign H shifter gears in GT5, I know).
I wonder if its a problem with GT5 + G27 profile as it dosent have sequential on it. Hmm.

The fact it is changing up and down shows its working tho, problem being it does not change from H shifter to sequential, even tho you have done, with the hardware.
Can you check a PC game? as you can configure it as you like on them.

liquid07

Any joy getting it to work trk?
What I ment was sequential only shifting to 2nd and back to 1st (same problem you have) when the gears are assigned to H shifter and also sequential at the same time on PC games (not possible to assign H shifter gears in GT5, I know).
I wonder if its a problem with GT5 + G27 profile as it dosent have sequential on it. Hmm.

The fact it is changing up and down shows its working tho, problem being it does not change from H shifter to sequential, even tho you have done, with the hardware.
Can you check a PC game? as you can configure it as you like on them.

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Well I am at work now but this is driving me crazy!! This evening I plan on trying it with another game. And if that doesn't work I will hook it up to my PC or MAC and see if It will register the movement on their.

If everything tests ok on the computer or other game on PS3 I guess I will try to delete my save game back to before 2.02 Hopefully that is where my last back up is. And reinstall the game. Hopefully it is a issue with GT5 since I am getting a signal at the plug and the pots tested good three times. And when in sequential mode it floats back to the middle from first or second values change so you would think the next time I pull back on the shifter it would go into 3rd gear.

Does anyone know why sometimes the gear number goes from being bright and solid in color to transparent? I'm not infront of my game but I was thinking that is when the engine stalls, can someone elaborate on this?

Well my sequential works with Dirt, and not with GT5 I can even switch the pattern around in Dirt but still only 1st and 2nd gear for GT5. And since I hardly ever play Dirt anymore I guess this will go in my closet because I think I am done trying to do detective work.

I hooked it up to my pc to test it out but I could not find a driver for a G25 and since the computer registers it as a G27 since that is the only driver I could find, it doesn't recognize sequential mode so therefore I could not test it that way. Maybe if I had another game but I was just trying to test it in Netkar but that program is not very user friendly it wouldn't recognize it the mode at all.

Thanks for your help guys.👍

so I was thinking of another mod, my current g25 is now working again after tightening the two bolts within the shifter, but now I want to do another mod. I would like the option of RHD shifter. So I order a G27 shifter off of ebay, can I make a new cable running from the base to somewhere in the middle of my cockpit and have a splitter with two db9 on one end for g25 and g27 shifter so when I choose to go RHD I have it available to me. or just run a custom extension cable and switch shifter that way

bearair

so I was thinking of another mod, my current g25 is now working again after tightening the two bolts within the shifter, but now I want to do another mod. I would like the option of RHD shifter. So I order a G27 shifter off of ebay, can I make a new cable running from the base to somewhere in the middle of my cockpit and have a splitter with two db9 on one end for g25 and g27 shifter so when I choose to go RHD I have it available to me. or just run a custom extension cable and switch shifter that way

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Should work. At one point, I had both the G27 shifter for H-shifting and G25 rewired shifter for sequential shifting. Both were connected to a DB9 manual switch (1 female IO and 2 male interfaces). Example on ebay. So, it was just a button press to switch between manual and sequential shift.

trk29

Yes that is correct I am playing GT 5 H pattern works fine but sequential still only shifts from 1st to 2nd.
I also wonder if deleting my save data and use my back up per 2.02
I didn't even think to try another game, I will try that this evening.

With what you saw with your pc game is the same thing?

Click to expand...

Sorry, I've never tried the modded G25 shifter on GT5, only on the PC.

itrdc5

Should work. At one point, I had both the G27 shifter for H-shifting and G25 rewired shifter for sequential shifting. Both were connected to a DB9 manual switch (1 female IO and 2 male interfaces). Example on ebay. So, it was just a button press to switch between manual and sequential shift.

Click to expand...

did you have to rewire the switch box at all?

can a net new cable ("crossover/converter")be made to run from the new g27 into the g25 base, I hate hacking something in perfect working condition.