2018 Chevrolet Express, Door Locks

Hey Guys, trying to install a remote start on a 2018 chevy express that already has power locks
when I check the lock and unlock wire listed below
I read 12vdc to ground on both wires with or with out pressing the lock and unlock switch
I know that I am the right connector because when I unplug the connector the locks don't work
not sure if I am reading the wiring wrong but should negative.
thanks in advance any help will be greatly appreciated


Power Lock      pink/black      -      driver kick or BCM under pass dash, gray plug, pin 12           
Power Unlock      orange/black      -      driver kick or BCM under pass dash, gray plug, pin 11

Sounds correct. Try putting your voltmeter on the pink/black and then lock the doors. The signal should go to ground when you press lock.

Try the same with unlock and the orange black wire, you should see the voltage drop to ground when you press unlock.   

Hope this helps.

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Lectric Guy

Thank you

I noticed my digital meter does not provide enough of a load to detect changes, I will try with a test light
if I can ask one more question I am a Scytek astra 4000 security/remote start on my 2018 chevy express
when I test ignition wire (pink) I read 3.9 volts it does not seem to change when I turn the key to start
since I can get to the black ignition connector, there is a large connector on the base of the steering column
that I believe it provided power the ignition switch, I have located the brown accessory wire from the ignition switch
but I have several pink wires 1 provides constant 12 volts when key is on other provides 3.9 volt when the key is on
I assume that when the ignition switch is turn start position I should read 12 volts and zero after the car starts and I release it
so I am a bit confused I have installed one of these on my 2009 Ford E 250 with out any problem if someone can shed some light it would be greatly appreciated.
Sorry for being so long winded (thank you in advance)

I also have a starter wire on my Scytek that I am not sure if it needs to be connected (below is the chevy wiring which of the pink wires should mi ignition wire be connected to )an lastly is there a way to bypass the immobilizer ?

Ignition      pink      +      ignition switch, black 6 pin plug, pin 2

Second Starter     pink (R Code) (see Tech Doc 1605)      +9600 ohms      ignition switch, black 6 pin plug, pin 5

Accessory      brown      +      ignition switch, black 6 pin plug, pin 3           

Second Accessory      same as second starter      +6300 ohms     

Starter      violet (for starter kill only)      +      starter or underhood fuse box, lt. gray 56 pin plug, pin E1 (?is wire required ?)

Tachometer      dk. blue/white (gas)      ac      ECM on driver fender, black 73 pin plug, pin 60 ( what should the voltage be when engine is running

Do not use test lights!!!! ever :V: :V: :V: Newer vehicle are very sensitive and you could burn out the bcm very easy with a test light, even one labeled "computer safe". always use dmm. Sorry but if i help prevent one thing being damaged by test light.

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33 years as a installer now just a retired old guy. Favorite thing to install/topic are remote starts/car alarms. Stop using test lights!!!

Set your meter to Ohms, Diode test or continuity. Ground one lead and attach the other lead to the wire. When you press the appropriate switch, it should show near 0 0hms while the button is depressed. Or put the meter to DC volts, connect the red lead to a known good 12 volt source, black lead to the wire, when you press the switch, it will then read 12 volts.

thank you for the warning mgoetz74 I really appreciate it

thank you for the info I will try as you say, it appears that circuit is sinking so placing meter red lead on 12 volt source makes sense since wire will go to ground when switch is pressed

OK Guys,

I have id 99% off the wires to connect my SCytek Astra 4000 remote starter, I have not been able to ID the starter wire here's the 2018 chevy express switch wiring
if someone has done this and can help ID the proper wire it would be greatly appreciated (
it looks like the connection should be made to the second starter wire but I am not 100% sure I don't want to damage my ECM I did locate one pink wire that drops to zero volts when cranking and back up to 12 volts after engine starts running

Starter      violet (for starter kill only)      +      starter or underhood fuse box, lt. gray 56 pin plug, pin E1           
Second Starter      pink (R Code) (see Tech Doc 1605)      +9600 ohms      ignition switch, black 6 pin plug, pin 5           
Ignition      pink      +      ignition switch, black 6 pin plug, pin 2           
Accessory      brown      +      ignition switch, black 6 pin plug, pin 3           
Second Accessory      same as second starter      +6300 ohms
Keysense      same as second starter       

Thank you in advance

Do yourself a favor and get a data bypass. I like Idatalink myself. I’ve never used a skytek system so I would hardwire the bypass to the module. Depending on the options your truck has the install isn’t difficult.

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If i Can't Install it    I Don't need it   Joe

I would have to disagree.. Test lights are perfectly fine if you know how to use them correctly.. Perfect for ignition wires, and finding negative locks. Just don't be a idiot and try to find can wires / test wires in yellow loom. But again this my Personal opinion.