Question about the 3 Amigos "Hummer" mod

apex944

Active member
Sep 9, 2015
27
5
Pittsburgh
So I have seen a number of videos on the "Hummer" mod where the wires inside on the shuttle valve assembly are cut and connected as to bypass the original circuitry. My question is.... What does this mod do to the 4wd, TC etc. systems assuming everything else is working correctly? Does it stop TC from functioning or stop ABS from functioning?

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There is no functional change. The only change is to guide electrical connections outside from printed circuit board because it has contact troubles.
This "shuttle valve" is specially useful when braking and its function is to determine what kind of treatment should ABS system choose:
When you depress brake pedal slightly, no side of this valve will activate contacts. Then ABS lets you brake as in non-ABS mode. When you depress more brake pedal it will reach enough pressure to move a contact, and then ABS lets you brake as usual, but when a wheel tends to stop before than the rest, modulator will discharge brake pressure from this wheel brake line to avoid it blocks its turn.
And when you suddenly depress brake pedal desperatelly, then both shuttle valve contacts activate, and ABS then, removes your foot pressure, uses its own modulator pump, and each wheel anti block valve, in order to stop the car in the shortest distance, with its four wheels revving to zero simoultaneously.
So, there are three options and the automatics choose is trough shuttle valve contact .

I hope my spelling is understandable
Regards
 

special ed

Well-known member
Apr 11, 2012
195
117
Elsinore
The circuit is just looking at ohms of resistance to ground. All you are doing is removing the ground circuit from the inside of the modulator and bypassing the failed connection in there. There is no need for it to be wired inside the abs module.
 
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apex944

Active member
Sep 9, 2015
27
5
Pittsburgh
Finally got around to doing the Hummer mod. Unfortunately after putting the SVS cover plate back on connecting the 2 wires (1 to ground and 1 to Yel/Grn) I still have all the Amigo lights. There were a number of possibly incomplete DIYs out there so I was not sure exactly what the final steps were regarding the ECU code clearing. I have a simple Bosch OBD code reader that can clear DTCs. Do I now need a specialized scanner clear the SLABs codes?

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rovercanus

Well-known member
Apr 24, 2004
9,660
251
Yes you will have to reset it with something that can read the SLABS module. Some codes thrown are soft codes meaning that they will reset themselves if the issues are ok and the vehicle has reached 12 MPH, Others are hard codes that will need an external reset. Luckily for you there are lots of options out there now that are inexpensive.
What led you to Option B if you didn't have a code reader that would read the system? You may still have other problems.
 
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apex944

Active member
Sep 9, 2015
27
5
Pittsburgh
>> What led you to Option B

I was doing coils and waiting for a new intake gasket so I decided to tear into the 3 Amigo light issue. Returning the wiring to as it was wont be an issue as I ran the original wires from the plug to outside the unit also.

Where are the other options explained. I searched for a while with no luck.
Any recommendations on a unit to reset these codes?
 

mlnnc

Well-known member
Mar 23, 2008
269
32
Charlotte
As others have written, Option B restores ABS, traction control and hill descent control functions.

It does not bypass the ABS system.

It bypasses a very common solder joint failure point buried deep in the ABS modulator.

Here is a link to a "reasonably-priced" scan tool that others on another DII forum like. I don't own one, so I can't vouch for it personally.


Where are you located? There may be someone near you who can help you out.

Also, your truck's ABS system may have other faults not related to the shuttle valve switch electrical fault. My truck had the SVS fault ~ago and I did Option B, but since then my truck has had wiring faults with two of the ABS wheel speed sensors. That's why it is important to have (or have access to) a scan tool that will read ABS codes.
 
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apex944

Active member
Sep 9, 2015
27
5
Pittsburgh
>>> I did Option B, but since then my truck has had wiring faults with two of the ABS wheel speed sensors.

And did these faults throw any codes that showed on the dash? Or did the option B hide them requiring you to scan the OBD for faults?
 

apex944

Active member
Sep 9, 2015
27
5
Pittsburgh
ok I was able to read and then clear all codes and the amigos with the i930. Had to drive around the block a few times and clear them twice actually. But they are gone!
 
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