Start of SRT-10 "Start Button" retrofit project

[Tomeygun]

In '02, I installed a Honda S2000 start button in the cigar lighter hole on my '01 Dodge. The size was identical. Wiring was tricky, since two circuits need to be shut off while one is turned on during cranking. This is really important, because some electronics in the trucks really do not like the "noise" and voltage drop in the electrical system when the starter is activated. The Honda button is similar to the SRT button, except it has a light in it. I wired the light into the Wait To Start indicator on the dash, so the switch glows red during the instrument cluster bulb test and when the heaters are activated. It is not actually wired into the heater themselves, rather it just mimics what the light on the dash is doing. That is, the start button light goes out when the light on the dash goes out. Anyway, for the actual start cicuitry, I had to use three relays. Two are used to turn off circuits during cranking, and one is used to activate a circuit. It ended up working great, and it always raises a passenger's eyebrow when I push it.



Here's a link to the wiring diagram I made. It's no the same wiring for an '03 truck, but you'll get the idea on what will need to be done. Just look at the wiring diagram for the '03 ignition switch, and you'll be able to see which circuits need to be on/off during cranking.



'01 Ram S2000 start button

Thanks for the wiring diagram... I am going to print it out and try to apply it to the 3rd gen, I thought of that too. All those circuits that have power and them loose it when the truck cranks over... hmmm, I think i am about done with this, I'm getting close

 

[TBrennan]

I'd double check the stock SRT wiring again, does it actually disengage the other circuits? I don't think it does if I remember correctly, it's just wired to the run location off the ignition switch. I wouldn't do any more work than the factory did.

 

[Tomeygun]

I'd double check the stock SRT wiring again, does it actually disengage the other circuits? I don't think it does if I remember correctly, it's just wired to the run location off the ignition switch. I wouldn't do any more work than the factory did.

The only ones it disconnects in the "RUN-ACC F985" lead... BUT my diesel has two extra leads off the ignition switch... SO, i will have to do the same, disconnect both "RUN-ACC" leads when the truck cranks



Namely, "RUN-ACC F1" (power windows), and "RUN-ACC-A31", (radio, cig lighter, power outlet, horn)



Now to draw up a final diagram before I hack into my steering column

 

[Tomeygun]

rough draft

Here is my first rough draft of the wiring...

PLEASE GIVE ME YOUR OPINIONS IF IT IS WRONG



Thanks!



ROUGH DRAFT STARTER BUTTON WIRING DIAGRAM

 

[mgonske]

Looks good, Tom--thanks to you and Evan both for all the hard work! Only two comments to your wiring diagram:



1. I don't think you want to use a hot (all the time) +12V input to the starter switch (or it will work anytime anyone pushes it--key or no key--and that could be really bad with a 6-speed parked in gear)--instead use the RUN-A21 circuit from the key switch.



2. Actually, this one is a question--why not disable the RUN-A38, and RUN-C1 circuits which are also disabled by the factory switch in the start position?



BTW, the RUN-A21 circuit is the one I have my IssPro TTM wired into to keep energized, and keep the truck running after I remove the key until the TTM thinks it has cooled down enough.

 

[Tomeygun]

Looks good, Tom--thanks to you and Evan both for all the hard work! Only two comments to your wiring diagram:



1. I don't think you want to use a hot (all the time) +12V input to the starter switch (or it will work anytime anyone pushes it--key or no key--and that could be really bad with a 6-speed parked in gear)--instead use the RUN-A21 circuit from the key switch.

Good thinking, BUT remember the switch only activates the relay, which without the power from the key, the relay will only click, but there is no power to sent because the key is not in the #2 position

2. Actually, this one is a question--why not disable the RUN-A38, and RUN-C1 circuits which are also disabled by the factory switch in the start position?



BTW, the RUN-A21 circuit is the one I have my IssPro TTM wired into to keep energized, and keep the truck running after I remove the key until the TTM thinks it has cooled down enough.

Well, look at this SRT wiring - SRT off-run-start pic - It does not shut off run F102, But is does shut off Run-ACC, (in another diagram)... So why should I?



I asked one of my Techs here, And he said the shutdown is mostly meant for acc. 's like the radio etc...



We will see, I might do all the others too, If I can find the room for all the Relays... cya!

 

[Evan A. Beck]

SRT-10 wiring diagrams do no good for what we are going to do. Only thing we need is a pinout of the button.



On the '03 Cummins, since thats the wiring diagram I have in front of me, FOUR circuits need to be cut off during cranking:



RUN C1: HVAC system

RUN-ACC F1: Power windows

RUN-ACC A31: Radio, instrument cluster, cigar lighter

RUN A38: Airbags, ABS



Circuits A21 and A41 (start circuit) are activated during cranking. Everything else needs to be shut down. Voltage drop for the accessories on the above four circuits could cause problems like blown fuses or electronic module failure.



Also looks like the SRT button is a 6-pin. Pinout?

 

[Tomeygun]

SRT-10 wiring diagrams do no good for what we are going to do. Only thing we need is a pinout of the button.



On the '03 Cummins, since thats the wiring diagram I have in front of me, FOUR circuits need to be cut off during cranking:



RUN C1: HVAC system

RUN-ACC F1: Power windows

RUN-ACC A31: Radio, instrument cluster, cigar lighter

RUN A38: Airbags, ABS



Circuits A21 and A41 (start circuit) are activated during cranking. Everything else needs to be shut down. Voltage drop for the accessories on the above four circuits could cause problems like blown fuses or electronic module failure.



Also looks like the SRT button is a 6-pin. Pinout?

I was afraid you were going to tell me that. Well I better buy a few more relays...



BTW - what about the RUN-F102, the SRT does not shut it off when it cranks. . but anyway... I guess if you are wiring it, you may as well do it right



here is the pinout



That has an output of the clutch switch, which is true, but I think our clutch switch is involved in a ground... hmmm...

 

[TBrennan]

Might want to source some DPDT relays so you won't so many in total.

 

[Evan A. Beck]

As for the RUN-F102, pay no attention to that. Engine management systems between the V10 (SRT) and the diesel are quite different. Pretty much nothing crosses over.



So only two of the six pins are being used on the button?

 

[Tomeygun]

As for the RUN-F102, pay no attention to that. Engine management systems between the V10 (SRT) and the diesel are quite different. Pretty much nothing crosses over.



So only two of the six pins are being used on the button?

1) I cant seem to find a automotive style (read large amperage) DPDT relay?



2) evan - I thought that was funny too, so what does the other pins do?? I guess I will have to hook up some weak power and break out the meter

 

[rbattelle]

1) I cant seem to find a automotive style (read large amperage) DPDT relay?

I really like these. 35A capacity, small package.



-Ryan

 

[Tomeygun]

I really like these. 35A capacity, small package.



-Ryan

Sounds good, I will check it out



Another question I have for ya'll,



Is what do you think about getting the power for the + side of the control on the relay from the lead in on the constant side of the relay ?



And then of course use button on the ground...

 

[Evan A. Beck]

1)I thought that was funny too, so what does the other pins do?? I guess I will have to hook up some weak power and break out the meter

Just look in the "Connector Pin Outs" section of the service manual. Everything should be there, complete breakdown of each connector's circuitry.

 

[Tomeygun]

Just look in the "Connector Pin Outs" section of the service manual. Everything should be there, complete breakdown of each connector's circuitry.

The "Connector Pin Outs" for the button are only showing using 2 of the six... The factory definitely does not use the other 4, the question is what do they do????

 

[mgonske]

The "Connector Pin Outs" for the button are only showing using 2 of the six... The factory definitely does not use the other 4, the question is what do they do????

Go ahead and check them out with your meter--maybe we'll get lucky, and it will have two normally closed momentary open circuits, which would eliminate the need for two relay circuits



From the drawing you posted, it looks like this button may have a unique connector--how do you plan on hooking up your wiring to it?

 

[Tomeygun]

Go ahead and check them out with your meter--maybe we'll get lucky, and it will have two normally closed momentary open circuits, which would eliminate the need for two relay circuits



From the drawing you posted, it looks like this button may have a unique connector--how do you plan on hooking up your wiring to it?

I will do the meter check this weekend, and I hope to find a plug that may fit the two prongs I need, I have a whole storage room of factory plugs that we have pulled out of autos. foriegn, domestic, etc



And Then i hope to go to the junk yard and find a few ingintion harness. . and then... . blah,blah,blah, you get the idea



My plan is to make this plug and play, no cutting wires

 

[Tomeygun]

almost forgot, i found this thread about the install on some 1500's



http://www.dodgetalk.com/forums/showthread.php?t=27537&highlight=start+button



I have not read in full yet, should be good though

 

[TBrennan]

Did a quick look around and I couldn't find any good sources for DPDT high amp (30 amp +) relays either, odd. The one posted above is OK but I didn't see a "Quick Connect" version, meaning you would have to solder all the wiring permanently to the relay which is not a big deal, I just prefer using the QC tabs for ease of installation and replacement.

 

[rbattelle]

Also notice the one I posted is a separate-type, which means you get 2 relays in 1 package... greatly reduces the space requirements if you've got to run lots of relays.