Hood Latch Switch Bypass

[TenshiWingusu]

I made an account just to post the fix for this, couldn't find it anywhere.... Your mileage may vary but this is what worked for me.

 

After having my alarm go off continuously with the hood ajar message I unplugged the hood latch sensor to fix the issue but in doing so I lost my factory remote start, not an big deal during the summer but now that its 20 degrees out its an issue. I dislike spending $100-$200 to replace a part that works fine because the $1 electrical switch integrated into it broke. The BCM seems to use logic on that pin other than high/low so the fix isn't as simple as twist the wires together. I ended up cutting the sensor/switch pigtail and wiring in a 10k ohm potentiometer and turning it till it worked. For my truck that was ~2100 ohms. The truck harness only utilizes two wires of the three pin connector and one of them is a ground. Solder in the 2100 ohm resistor in between the red and black wires as shown attached (don't forget to put the shrink tube on before) plug it in and the hood switch will be bypassed in the  "hood closed" position. keep in mind that you can now remote start with the hood open and peoples hands in there. Use at your own risk.

 

2015 GMC Sierra 1500 SLE 4x4 5.3L

[Linden16]

Hey im having the same exact problem on my 2015 chevy silverado 3500. I bought a new sensor and still have the same problem. So would your fix still work for mine?

[TenshiWingusu]

3 minutes ago, Linden16 said:

Hey im having the same exact problem on my 2015 chevy silverado 3500. I bought a new sensor and still have the same problem. So would your fix still work for mine?

Its possible, but if its a new switch the problem could be elsewhere, like the BCM. I would put a multimeter on the new switch and see what it says for resistance in both positions.

[Linden16]

Yeah i put a new sensor in hoping it would fix the problem but nope. And its weird. It only does it when the truck is cold. Once I start going after 2-4 minutes it just stops and doesn’t ring again.. its still annoying though when it rings

[TenshiWingusu]

2 minutes ago, Linden16 said:

Yeah i put a new sensor in hoping it would fix the problem but nope. And its weird. It only does it when the truck is cold. Once I start going after 2-4 minutes it just stops and doesn’t ring again.. its still annoying though when it rings

is the switch on the 3500 not integrated into the hood latch? Did you replace the whole latch or just the switch?

[tbarn]

The yellow wire is for Hybrid vehicles. Otherwise not used.

[tbarn]

732 ohms open, 2312 ohms closed is the spec. Give or take some in real life.

[Linden16]

6 minutes ago, TenshiWingusu said:

is the switch on the 3500 not integrated into the hood latch? Did you replace the whole latch or just the switch?

Yeah its the whole late assembly correct. So i installed that and still have the same problem yup.. not sure what else could be causing it. And like i said it only rings when the trucks cold. After a few minutes of driving it stops

[Linden16]

Latch *

[Linden16]

21 hours ago, TenshiWingusu said:

is the switch on the 3500 not integrated into the hood latch? Did you replace the whole latch or just the switch?

So how come you cant just hook the wires together without a resistor? What would happen if you did that

[TenshiWingusu]

26 minutes ago, Linden16 said:

So how come you cant just hook the wires together without a resistor? What would happen if you did that

The Control module is looking for a specific voltage/current for hood open and closed. Not just continuity. They use additional logic for fault diagnosis. That's how it knows the difference between being closed vs unplugged. Just twisting the wires together sends 12vdc to the module which likely won't damaged it but possibly could if it's made for less input.

Edited February 18, 2019 by TenshiWingusu

[Linden16]

9 minutes ago, TenshiWingusu said:

The Control module is looking for a specific voltage/current for hood open and closed. Not just continuity. They use additional logic for fault diagnosis. That's how it knows the difference between being closed vs unplugged. Just twisting the wires together sends 12vdc to the module which likely won't damaged it but possibly could if it's made for less input.

Oh ok makese sense. I wonder if theres a way to silence alarms that would work. Cause i mean it only does it for like 3-4 minutes when the trucks cold then it stops. Its so weird idk what would cause that.

[TenshiWingusu]

10 minutes ago, Linden16 said:

Oh ok makese sense. I wonder if theres a way to silence alarms that would work. Cause i mean it only does it for like 3-4 minutes when the trucks cold then it stops. Its so weird idk what would cause that.

You should be able to unplug it and have no issues other than no remote start.

[Linden16]

8 minutes ago, TenshiWingusu said:

You should be able to unplug it and have no issues other than no remote start.

But yeah i want my remote start thats handy lol. Buy a $60000 truck and have no remote start cause of a stupid hood sensor. Ill have to call the dealership and see. But i know theyll just charge you a arm and a leg to fix it

[TenshiWingusu]

31 minutes ago, Linden16 said:

But yeah i want my remote start thats handy lol. Buy a $60000 truck and have no remote start cause of a stupid hood sensor. Ill have to call the dealership and see. But i know theyll just charge you a arm and a leg to fix it

I hear ya. I would check the resistance on the new switch in both positions, you can force the latch closed with a screwdriver then pop it with the interior hood release. If the switch is in the spec mentioned above it's either bad wires somewhere or the control module has issues.