Fortin INT SL+ Bypass Mystery, 2003 Chevrolet Silverado

1 year ago I installed a Viper 4706 RS into my son's 2003 Silverado ss with a Fortin INT SL+ bypass module (service number 002102 074369). Works great. I bought an identical (red-not blue) 2003. I am installing a 5706V RS and alarm with same bypass (service number002102 091815).

Followed the exact same wiring install. When I try RS, it turns over but does not run. I have tried changing Tach sense from virtual (bypass module orang/black to RS violet /white pin 12) to wired (white behind instument panel to violet /white). Both cases the module does not light on command and the dash security light stays lit. If I remove the module and program it into my son's truck it works fine. It acts like it programs fine in my truck (light comes on, flashes after you turn the key, start with key, then light goes out.)
Called Fortin tech support and they said I had to have Firmware 0.53 flashed. The INT sl+ worked fine on the 1st install so I bought it again just so I would not have to flash it. No install shop near me is interested in flashing it. So now I'm questioning my install.
     viper          Int-sl+          SS     notes
main 6-pin                              
h-1     red     +12V constant input               red     ignition harness
h-2     black     - chassis ground                    chassis ground
h-3     brown     -horn honk output               black     steering column
h-4     white/brown     pin87A paring light isolation                    
h-5     white     Pin 30 light flash relay     pink/black     parking light          
h-6     orange     gnd when armed                    
door lock 3-pin                              
     blue     -unlock output     white     unlock          
     empty                         
     green     -lock output     lt. blue     lock          
Remote start 10-pin                              
1          not used                    
2     red/black     +fused 12v acc/starter input               red     ignition harness
3     pink/black     +flex relay #87A                    
4     pink/white     +ignition 2 /flex relay out #30               white     Ign 2 ignition harness
5     red     +12v constant ign 1 input               red     +12v ignition harness
6     green     +starter input               yellow     wire cut- key side
7     violet     +starter out               yellow     +starter ignition harness-starter side
8     orange     +accessory out               orange     1st accessory ignition harness
9     red/white     +12v constant ign 2               red     +12v ignition harness
10     pink     +ignition 1 in/out     pink     ignition     pink     Ign1 ignition harness
          added relay                brown     2nd accessory ignition harness
Aux harness 24 pin                              
1     pink/white     -ign 2/flex output                    
2     blue/white     -2nd status/rear defog out                    
3     red/white     -trunk release output                    
4     black/yellow     -dome light output                    
5     dk blue     - status output     blue      - when running          
6     white/black     -aux 3 output                    
7     white/violet     -aux 1 output                    
8     orange/black     -aux 4 output                    
9     gray     -hood pin input               n/o     
10     blue*     factory horm input (set)                    
11     white/blue     activation input                    
12     violet/white     tachometer input               white     instrument panel
13     black/white     -neutral safety input               ground     
14     green/black     - factory alarm disarm out                    
15     green**     -door input     orange               
16     empty                         
17     pink     -ignition 1 output                    
18     violet     +door input                    
19     violet/black     -aux 2 output                    
20     brown     +brake shutdown input                    
21     violet/yellow     -starter input                    
22     gray/black     -diesel wait to start                    
23     orange     -accessory output                    
24     green/white     -factory alarm arm output                    
                              
               pink     ignition     pink     ignition harness
               purple     OBD2     purple      OBD2 plug
               white/black     unlock driver 2          not used
               green     n/a          
     INT SL+          purple/white     n/a          
               yellow/black     n/a          
               red     12V     red      ignition harness
               black     chassis ground          ground

This is from I spreadsheet that I cannot figure out how to upload.

regular key. we both have different head units. I re-installed the original radio and tried to re-program the bypass module without any success.

https://www.the12volt.com/installbay/file.asp?ID=1490
added an excel spreadsheet that is easier to follow.
"5706V in a 2003 silverado SS with fortin INT SL+" in vehicle wiring downloads.

Interesting problem. I've used a bunch of Fortin INT-SL+'s over the years. I like them and found them to be very reliable.

First things first. The 4706 and the 5706 are pretty much the same but do have some differences. The 5706 has the built-in Starter Interrupt, which you are using. Being as the engine cranks with both the key and the R/S, the wiring is correct at the vehicles cut Starter wire. The 5706 also has alarm functions and you can test to see if the INT-SL+ is providing door pin Status.

Next, I'm assuming this is just an omission, but the Vipers Brown (+) Brake Shutdown wire is not listed in your wiring. This wouldn't give you the symptoms you describe anyway but I didn't want to overlook anything. The Brake wire should be used as it provides useful info and shuts down the R/S'd engine at taken-over.

You are going wire to wire between the INT-SL+ and the Viper which is required with the DEI product and will make it easier to trouble shoot.

You mentioned that the INT-SL+ works properly in the sister vehicle and that it appears to program correctly in your Blue truck. Does the Viper remote control the door locks and the Parking Lights in your truck?*   You also mentioned that the Security Light comes on with a failed R/S. This would seem to be where the main problem lies. With Passlock2, the vehicle will crank but won't run due to the immobilizer cutting off the fuel.

* This part of the bypass working would indicate that the INT-SL+'s 14 Pin harness is plugged in right side up.

So, if the INT-SL+ programs properly in both trucks and works in your sons' truck and can control the locks and Parking Lights in your truck, let's try a few things to rule out the Viper.

Switch the INT-SL+'s Blue (-) While Running wire from the Vipers Dark Blue (-) Status Output to the unused Blue/White (-) 2nd Status Output wire. The Blue/White wire can also be used for Rear Defrost but the Factory Default setting is (-) Status Output. My thinking is that the INT-SL+ has learned the Passlock2 signal and needs the Vipers Status Output to tell the INT-SL+ that it's doing a R/S and to send that Passlock2 signal to the Violet J1850 wire. If there was something wrong with the Vipers Dark Blue wire and the Blue/White wire was OK, then this would fix the problem. If this didn't work, the next step would be to disconnect the INT-SL+ Blue wire from the Viper and using a jumper, connect it to Chassis Ground and the same time you press the Vipers R/S button.

AS for Fortins' recommendation...
I'm guessing that you have a H/W VER 2 INT-SL+ with the latest F/W 2.3.06. While this firmware has the latest fixes for your truck it also has some additional updates for other vehicles. Going back to 2.0.53 would eliminate those un-necessary fixes. I've never had a need to do this but... I could re-flash your module if needed.

-------------
Soldering is fun!

Kreg357...U are AMAZING.
"Switch the INT-SL+'s Blue (-) While Running wire from the Vipers Dark Blue (-) Status Output to the unused Blue/White (-) 2nd Status Output wire."--30second fix that I would not have thought of. Everything works great!

Brown RS wire was connected to white wire @ brake switch(ommision in spreadsheet.)
The 5706v does control the parking lights and door locks.

Preference of tach wire over virtual tach?
Does pin 13 black/white need ground(-parking brake input) or just leave unconnected?

Your professionalism and clarity in your post is greatly appreciated. This was a Christmas gift from my wife. She is so happy you were able to help.

Easy fix - Bad Viper output on Dark Blue (-) Status Output.

Figured that the Brake input was an omission.

I prefer going with the actual Tach wire at the back of the instrument cluster. Good signal that always works.

The Neutral Safety must be used. It must provide a (-) / Ground signal to allow a R/S. If you always use the Parking Brake when parked, you could go that way. With all the safeties built into the Auto Trans truck to prevent a R/S when not in Park, it's easier and acceptable to just connect that Black/White wire to Chassis Ground.

-------------
Soldering is fun!

perfect.
Is there anything that you think I should Diode isolate?

Depends. If your extra Accessory2 relay circuit is controlled by the Vipers' thin wire Orange (-) Accessory Output, a relay quenching diode might be in order. This would protect the Vipers Orange wire output from the relays' coil collapse pulse.

-------------
Soldering is fun!