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Jared D
Jared D, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1782
Experience:  Shop Supervisor at County Fleet
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I have a 2012 Chevy Impala Police car that I want to enable

Customer Question

I have a 2012 Chevy Impala Police car that I want to enable all of the options that were disabled. I need the horn to work, high beam lights, front radio speakers, dome light when doors are opened and so forth. I am un able to locate anywhere how to do this.
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Chevy. The Chevy Mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: Yes I have already got the rear windows and doors to work properly and the remote to lock/unlock doors.
JA: Great! What have you tried so far?
Customer: I have not tried anything yet with the remaining problems because there is no information out there anywhere as where to begin. I have read the manual that came with the car describing what has been disabled but no indication as how to reconnect them.
JA: Is there anything else the Chevy Mechanic should be aware of about your Chevy?
Customer: No everything is fine except the disabled items.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Chevy
Expert:  Jared D replied 1 year ago.


I have a fleet of about 500 police cars, of which 50 or so are impalas. Do you still need help with this?

What sort of diagnostic equipment do you have?

Customer: replied 1 year ago.
I do not have any GM diagnostic equipment at all. I am just a car owner that bought this piece of junk at an auction and need to get things working again. I am an electronics tech by trade and have also done much electrical work both on cars and houses. I always had the necessary information to do the work. That is what I need here, DETAILED INFORMATION, such as what to connect and where to connect it, jumper bypasses, wiring diagrams, anything else that will help,thank s George.
Expert:  Jared D replied 1 year ago.

Unfortunately, everything is disabled through the PCM and BCM through programming. The only way to activate it is with a GM compatible scan tool. We use a Tech 2. You could try to bypass he PCM and BCM with jumpers, relays, switches, etc, but I can't imagine how you would ever get it working correctly.

Customer: replied 1 year ago.
Well then let me pick your brain with this, does the tan wire, number 28 that goes into the bcm at connector 5, wire 18 need to be open or grounded for the horn circuit to work properly?
Expert:  Jared D replied 1 year ago.

The BCM grounds the horn circuit to make it operate. These two diagrams should help.

Customer: replied 1 year ago.
Well that is what I thought as well but when I grounded it still no horn, same with the headlight wires. They must have disconnected then in another way! On the headlights I show the high beam as wire tn/wh going into connector 4 position 16, but grounding this does nothing! I have no more ideas?
Customer: replied 1 year ago.
I can not locate the headlight relays or horn relays anywhere, according to my info they are supposed to be in the engine compartment fuse box but nothing is listed as them in the owners manual. Are they somewhere else and possibly removed?
Expert:  Jared D replied 1 year ago.

The headlights are grounded through the BCM also. I'm wondering if you could get a same year same engine used BCM and make it work.

They probably removed the relays and ran it all through the upfitter's police module. That's what our upfitter does.

Customer: replied 1 year ago.
Where are these relays located? They do not seem to be in the engine compartment box as indicated by the schematics and are not identified in the owners manual when looking at the engine compartment fuse box diagram?
Expert:  Jared D replied 1 year ago.

I don't list ant relays on the 2012. It looks like they are all activated via the BCM.

Customer: replied 1 year ago.
Well they show up on EBay as a 4 prong relay with a GM part number so they must be mounted in the BCM, I'll year it apart and look, thanks George.
Expert:  Jared D replied 1 year ago.

Let me know if you need any more info. I'm sorry I can't send more relevant diagrams over. There just isn't much available on these police cars.

Customer: replied 1 year ago.
Ok, let you know what I find out, thanks.
Expert:  Jared D replied 1 year ago.

Sounds good. Thanks!