How does the ignition switch work on a GM car?
The ignition switch now talks to the body control module (BCM) and it’s the BCM that initiates one of two relays. The second relay, the more important of the two, is controlled by the powertrain control module (PCM). And it only operates the starter relay after it’s satisfied that the correct key is in the ignition.
What’s the problem with my GMC Yukon Denali XL?
Have a 2009 Denali XL with many of the same issues identified here EXCEPT doors locking and unlocking and the rear window thing. Been fighting the gremlins for almost 3 years. Originally I though I had it narrowed down to a broken battery post in the battery when I seemed to be able to wiggle the posts and got everything to work.
Are there any electrical problems with my GMC Yukon?
Battery goes dead after door is open for a short period of time or a dome light is on for a short period of time. Had battery, alternator and starter tested – all fine. Was loyal Toyota guy but needed a bigger vehicle and no model from Toyota fits the bill. Starting to regret going with GMC
What’s the voltage on my GMC Yukon Denali?
I noticed last night while driving that my headlights would get brighter and the voltage meter would increase above 15 volts. The lights would dim and the volt meter would drop back to 14 volts.
The ignition switch now talks to the body control module (BCM) and it’s the BCM that initiates one of two relays. The second relay, the more important of the two, is controlled by the powertrain control module (PCM). And it only operates the starter relay after it’s satisfied that the correct key is in the ignition.
What is a typical GM starting system wiring diagram?
Click on the image here to pull up a PDF of a typical GM starting system wiring diagram. Depending on the year, model and engine of your GM vehicle, your starting system may be less complicated or use only some of the components shown here. For example, earlier anti-theft systems didn’t communicate the same way with the PCM.
Is the ignition switch part of the PCM?
The ignition switch now talks to the body control module (BCM) and it’s the BCM that initiates one of two relays. The second relay, the more important of the two, is controlled by the powertrain control module (PCM).
When does an ignition module need to be replaced?
If the light blinks, the module is good. If the light is blank or constant, the module is bad. Before you attempt to replace the control module, you must rule out other ignition system components. The module is expensive and replacing it is a laborious process. Check the ignition coil for a spark.
How to repair a 1980 GM Truck wiring diagram?
These diagrams include: Access our GM Full-Size Trucks 1980-1987 Wiring Diagrams Repair Guide by creating an account or signing into your AutoZone Rewards account. Once you sign in, follow these instructions to access our Repair Guides. Add your vehicle in Manage My Vehicles. Enter your vehicle details.
What kind of wiring diagram do you need for 1985 Chevy truck?
1985 chevy truck wiring diagram – You’ll need an extensive, skilled, and easy to understand Wiring Diagram. With such an illustrative guide, you are going to be capable of troubleshoot, stop, and total your tasks with ease.
Why is the engine harness short on my GM Truck?
Truck is in the dealer again. Long story short, FICM has been replaced 4 times, and now GM has to have an inspector verify that the engine harness needs to be replaced. They say there is a TSB that says that the Edge is causing the wires to heat up and possibly short out.
Is there a free wiring diagram for a GM Truck?
Access our free Wiring Diagrams Repair Guide for GM Full-Size Trucks 1988-1998 through AutoZone Rewards. These diagrams include: Fig. 2: Sample Diagram: How to Read and Interpret Wiring Diagrams
Where is the ignition switch on a 4×4?
Just a hunch, but I would start by tracking down all of the underhood fuseible links and testing them, and then try a new ignition switch. typicaly the ignition switch will switch will be in the circuit before the fuse block, and will switch power to the buss’ of the fuse block that are for switched accessories.
Where is the ignition switch on a Ford Ranger?
The ignition switch is at the base of the steering column, on top, and has a huge plug with a number of 10 AWG wires going to it. I think it’s probably the wire leaving the junction block by the brake booster, though, that is power for the whole truck and the most likely culprit.
Why does my turn signal on my Chevy Express van not work?
Chevy Express Van fuses diagram. when one turn signal works and one doesn’t it is usually the tail light contacts or the turn signal switch. If the front one works then usually the switch is working so verify the contacts for the light that is not working are all good.
Is there a problem with my Chevy Express 3500?
I have a 2004 chevy express 3500 van and having a similar problem as one previously posted with signal and tidal light issues but I’ve checked fuses under hood and seat and all seam to be good .
In this vintage, GM uses the ignition switch as a signaling device to tell the body control module the position of the lock cylinder. There’s one voltage when the key is in the lock position, another when it’s in the START, and a third when it’s in the RUN position. But the BCM should never see voltage when the key is in the ACC position.
How to replace a no start ignition switch?
GM Ignition switch replacement to fix a no start or intermittent start. Faulty ignition switch contacts can also cause the PassLock system to enable Click here to see step by step proceedures. http://www.thejunkmanadv.com/the-junk… Support the site, buy service manuals here : http://www.tkqlhce.com/click-7357719-… Loading…
Why is my GM no crank no click car not starting?
The starting procedure on these vehicles is fairly complicated and the root problem lies in the ignition switch. The ignition switch does NOT directly control the starter motor like in older designs. In this vintage, GM uses the ignition switch as a signaling device to tell the body control module the position of the lock cylinder.
Is there a spark in the ignition module?
There is no spark coming out of any of the ignition coils sitting on top of the ignition module. You may have taken your ignition control module (ICM) to Auto Zone to test it and the friendly boys in orange say it’s good, yet the vehicle will not start (all major auto parts stores such as O’Reilly, Pepboys, etc., test ignition modules for free).
What kind of signal does the ignition module need?
OK, moving on along… for the ignition module to create this Switching signal, it needs to receive a C ran k shaft P osition (CKP) sensor signal (this signal is usually referred to as the Triggering signal and in GM service literature it’s known as the 3X or 7X CKP signal).
There is no spark coming out of any of the ignition coils sitting on top of the ignition module. You may have taken your ignition control module (ICM) to Auto Zone to test it and the friendly boys in orange say it’s good, yet the vehicle will not start (all major auto parts stores such as O’Reilly, Pepboys, etc., test ignition modules for free).
OK, moving on along… for the ignition module to create this Switching signal, it needs to receive a C ran k shaft P osition (CKP) sensor signal (this signal is usually referred to as the Triggering signal and in GM service literature it’s known as the 3X or 7X CKP signal).
Click on the image here to pull up a PDF of a typical GM starting system wiring diagram. Depending on the year, model and engine of your GM vehicle, your starting system may be less complicated or use only some of the components shown here. For example, earlier anti-theft systems didn’t communicate the same way with the PCM.
The ignition switch now talks to the body control module (BCM) and it’s the BCM that initiates one of two relays. The second relay, the more important of the two, is controlled by the powertrain control module (PCM).