2007 scion tc viper 5901 ignition relay

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=117328
Printed Date: September 18, 2025 at 1:41 AM

Topic: 2007 scion tc viper 5901 ignition relay

Posted By: the12voltuser
Subject: 2007 scion tc viper 5901 ignition relay
Date Posted: October 28, 2009 at 8:07 PM

Hi, i have a question about hooking up Viper 5901 to Scion TC 07.

Yes, I've searched the forum and wouldn't have asked if found the answer. I am clear on all other wires except H3 harness from Viper 5901.

My question is: i have to use a relay to connect to ignition, but not sure which wires go to Viper 5901 H3 <-Relay-> Ignition.

Here is the wiring scheme for ignition from the service manual:
posted_image

Here is the H3 Remote Start wiring harness:
posted_image

Please look at pic below, and correct it.
posted_image

Replies:

Posted By: t&t tech
Date Posted: October 28, 2009 at 8:32 PM

You need a relay! But not for the purpose you have demonstrated! The relay is needed for your second starter, you already have two wires that can connect to your ignition circuit! The pink-ignition one and the pink/white- ignition two, the second starter wire is where the relay comes in, use the small 5 pin harness I believe it's the violet wire that sends a negative trigger signal to drive a relay!

Posted By: Mike M2
Date Posted: October 28, 2009 at 8:42 PM

I'm not getting it, why are you using a relay to connect the ignition up to this car? You simply connect the pink H3/1 to blue at the ignition harnes, and pink/ white H3/7 to the yellow at the ign harness. Then you must supply 12volts to 3/2 3/8 and 3/9 from the red at the ign harness.

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Mike M2
Tech Manager
CS Dealer Services

Posted By: Mike M2
Date Posted: October 28, 2009 at 8:45 PM

TT beat me to it. Do NOT just connect the two starter wires together, use a relay for it like he says...

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Mike M2
Tech Manager
CS Dealer Services

Posted By: Mike M2
Date Posted: October 28, 2009 at 8:47 PM

Man i still got it wrong! Don't connect anything to 3/8....

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Mike M2
Tech Manager
CS Dealer Services

Posted By: the12voltuser
Date Posted: October 28, 2009 at 8:52 PM

The pink-ignition one and the pink/white- ignition two. I understand that. So H3 doesn't need any relays? So why does the connection H3/2 refers to flex relay 87?

H3/1 Pink <--> IG1 Yellow
H3/7 Pink/White <--> IG2 Blue

The violet wire you referring to, is it from RS-OUT harness?

posted_image

I am confused then, do i have to connect these two?
ST2 <---> RS-OUT/3

I guess what i am after, is the clear picture which wire goes where.

Thank you.

Posted By: the12voltuser
Date Posted: October 28, 2009 at 9:07 PM

Ok. So this is what i do with H3 wires.

posted_image

Still dont know what to do with starter wire ST1(Green).

Can you guys describe in detail - "use a relay for it like he says..."

Thank you.

Posted By: the12voltuser
Date Posted: October 28, 2009 at 9:14 PM

Mike M2 wrote:

Man i still got it wrong! Don't connect anything to 3/8....

Sorry didnt see you post in time.

So this is correct now, for H3?
posted_image

Posted By: Mike M2
Date Posted: October 29, 2009 at 6:28 AM

You are correct now. You still need a second starter relay tho. The AUX harness you show above, violet wire, will drive the relay(86). 85 and 30 to 12volts, 87 to the second starter wire in the car.

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Mike M2
Tech Manager
CS Dealer Services

Posted By: the12voltuser
Date Posted: October 29, 2009 at 12:21 PM

Mike very appreciated!

If it's possible can you explain why i need to use a relay for a second starter?

Hope this looks correct.

posted_image

Posted By: the12voltuser
Date Posted: October 29, 2009 at 3:13 PM

Mike M2 wrote:

You are correct now. You still need a second starter relay tho. The AUX harness you show above, violet wire, will drive the relay(86). 85 and 30 to 12volts, 87 to the second starter wire in the car.

Or should i use SPST Relay as it doesnt have 87a connection?

Thank you.

Posted By: t&t tech
Date Posted: October 29, 2009 at 3:34 PM

It doesn't matter, SPDT, or SPST relay will work! If you already have either use it, no point in purchasing another to do the same!

Posted By: t&t tech
Date Posted: October 29, 2009 at 3:40 PM

The second starter relay is to energize the second starter wire! There isn't a second one on the heavy gauge harness because it isn't present on all cars, so dei made it so in the event there was one you could still power it using the trigger wire! If you're wondering why you couldn't just tie both starter wires together it's because they are separate from the factory for a purpose, it's best to leave it that way!

Also here's how i wire that second starter relay

Pin 85- the starter trigger wire negative,

pin 86- ignition

pin 30- constant twelve from the ignition harness not the ignition wire why (because the ignition here would have to draw the current to power the second starter circuit as well as it's own circuits)

pin 87- second starter wire in car!

Posted By: the12voltuser
Date Posted: October 29, 2009 at 5:16 PM

t&t tech wrote:

Also here's how i wire that second starter relay
Pin 85- the starter trigger wire negative,
pin 86- ignition
pin 30- constant twelve from the ignition harness not the ignition wire why (because the ignition here would have to draw the current to power the second starter circuit as well as it's own circuits)
pin 87- second starter wire in car!

Thank you!

T&T, can both variations be used to connect this relay?
The only thing i am confused in your directions, is that we already connected both of Ignition wires to H3 harness:

posted_image

But then again it needs to be reconnected for second starter relay?

Is it possible to give adjustments for both pictures?

So i guess here is the new diagram.
posted_image

I very appreciate your help, i want to make sure about each wire, before i go to install this thing this weekend.

Posted By: syl20rochon
Date Posted: October 29, 2009 at 5:20 PM

Make: scion
Model: TC
Year: 2007

FUNCTION DATACOLOR LOCATION POLARITY PICTURE
+12 Volts Red Ignition Harness +
Comments: Additional 12-volt power wire: WHITE.
Ignition Blue Ignition Harness +
Ignition 2 Yellow Ignition Harness +
Accessory Gray Ignition Harness +
Starter Black Ignition Harness +
Starter 2 Green Ignition Harness +
Key Sense Black Steering column harness -
Comments: Pulsing this wire will disarm the OEM alarm without unlocking any door.
Tachometer Black Diagnostic connector AC
Parking Lights Brown Headlight switch -
Comments: Can use BROWN (+) wire at top connector of fuse box.
Brakeswitch Blue Brake Switch +
Parking Brake Black Parking brake Switch -
Lock Green Driver's kick panel -
Comments: Will arm & lock at the same time. To test rotate key in driver's lock cylinder.
Unlock Purple Driver's kick panel -
Comments: Will disarm & unlock if double pulse is used. To test rotate key in driver's lock cylinder.
Trunk Release Orange Driver's kick panel -
Arm Arms With Lock Driver's kick panel -
Disarm Disarms with Unlock Driver's kick panel -
Horn White Steering column harness -
Doorpin separate doorpin Fuse box -
Left Front Doorpin Orange Fuse box -
Right Front Doorpin Blue Fuse box -
Trunk Pin Purple Fuse box -

Security: OEM ALARM,TRANSPONDER

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Sylvain Rochon
MECP security specialist
Tech support for remote starters
26 Years of experience counts
I'm here to help.

Posted By: Mike M2
Date Posted: October 29, 2009 at 5:52 PM

Your dead on now! 86 can be either ignition or battery, won't matter. I used to have a guy work for me that did 4 toyota's before i fired him for poor work. On all the cars he tied the starter wires together and they worked fine...at first. Withing a month all 4 cars came back with the AM1 fuse blown in the car. The cure was to add a relay of coarse. I couldn't tell you why the fuses blew or why they need to be separated, but i know they do need to be....

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Mike M2
Tech Manager
CS Dealer Services

Posted By: syl20rochon
Date Posted: October 29, 2009 at 5:55 PM

If the manifacturers makes vehicules with 2 seperate ignitions, starters, accessory wires...there is a reason and our job is to duplicate what they built not modify it...relays are a technicians best friend in many cases....

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Sylvain Rochon
MECP security specialist
Tech support for remote starters
26 Years of experience counts
I'm here to help.

Posted By: the12voltuser
Date Posted: October 29, 2009 at 6:10 PM

So i guess either will work:

per T&T
posted_image

per Mike

Thank you.

Posted By: syl20rochon
Date Posted: October 29, 2009 at 6:13 PM

I normally connect the 2nd starter as follow...

85= small purple wire from the 5 pin connector
86 & 87= +12V
30= Second starter wire of vehicule.

-------------
Sylvain Rochon
MECP security specialist
Tech support for remote starters
26 Years of experience counts
I'm here to help.

Posted By: t&t tech
Date Posted: October 29, 2009 at 9:01 PM

Yup! Either relay setup will work mr.12voltuser!

Also mike had that experience with a fellow installer at the shop i work, he used six amp diodes to isolate the wires, the second starter fed of the first one, when he's really lazy he just ties them in together, alot of his customers come back with problems. Suprisingly the owner of our shop still keeps him on because he doesn't know better either!

And don't blame me cuz i try to teach them, but they never take my advice, because i have less experience than them! LOL, funny thing is, when they can't figure the problems, you wouldn't guess whom they come to for help! posted_image

Posted By: Mike M2
Date Posted: October 30, 2009 at 6:41 AM

Your last diagram states green as ignition on 87, that should be 2nd starter. Both are actually the same diagrams!

Think of a relay like a light switch in your house. applying 85 and 86 with a ground and 12volts is like you flipping the light switch(both terminals are the same so it never matters which has 12v and which has ground). 30 is the power input and 87 is output(whatever you apply to 30 will come out 87 when you flip the switch). Simple?

Now 87a is only used if the power output needs to be isolated. For instance, say a wire has a ground at rest and you need to apply 12volts to just one end of this wire. You would cut the wire and connect the grounded end to 87a. This would allow the 12volts to go where you want when you flip the switch and go back to ground when you release it.

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Mike M2
Tech Manager
CS Dealer Services