Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Just a quick question that should help me to isolate your concern.
So it is not blowing the 15A fuse...you go out under the hood to check and with key on, and there is no power to eng.Control Fuse when you check with a test lamp.
Are there any other symptoms or related items that you may find not working when the engine doesn't start.
Let me know
Important to my helping you, I need to know if INJ 1 fuse and INJ 2 fuses have no power along with the ENG CTRL fuse. Also check A/C CRUISE 15A fuse in the same underhood electrical center.
I'm going to send you the schematic for the systemCustomer and you'll see why I have asked the questions that I did.
You'll notice that the Eng Ctrl, AC CRUISE both receive their power from the Ignition relay.
The Ignition Relay is also located in the same Underhood Electrical Center 2 where the Eng Ctrl fuse is located.
If the power source for Eng Ctrl fuse is missing, then either the relay is malfunctioning, or the primary side to the Ignition Relay is not being energized.
The Relay primary side receives its power directly from the pink wire at the ignition switch. This tells me that you may have an Ingnition switch failing, or the connections at the switch may be intermittant.
The other power source to check is the secondary Ignition Relay power source. If the Red wire to the Relay is Intermittant, then there is a possiblity of a fuse link problem.
Focus on the Ignition Switch Electrical portion of the switch and possible switch intermittant failure or the Ignition Relay. The electrical portion of these ignition switches can and do fail.
This information should be all that you need to isolate your problem. If you can't see a problem, you may need to wait for the problem to happen in order to isolate it.
I sincerely, XXXXX XXXXX information will help
Have A Great Day
I would focus on the Ign Relay and Ignition Switch.
When you look closely at the circuit, if the Eng Control Fuse has no power on both sides, and the A/C Cruise Fuse has power, then the problem lies in right in the fuse holder contacts.
Or you should turn the Underhood Electrical Center 2 upside down and check the connections closely to the Eng Control Fuse. Backtrace to the Splice and then to the Relay. There's not much more to it.
So that we are sure we have power where we should.
When you cycle the key on and off, you should be able to feel the relay click. Place your fingers on the relay, and have someone turn the key on and off for you.
That will tell you that the Pink has power, and that the ground to Cell 14 is OK.
At your ignition relay, you should have 12v. in 2 of the pin locations.
Key on, there should be power to the pin where the red wire is located, and where the pink wire is located. You can pull the relay and probe this with a test light. If The red wire has no power,
That is where the #30 and #85 locations are on the relay both should have 12v with key on. If not we'll go from there.
If the relay doesn't click when key is turned to run, let me know.
There is a real good chance that when you are probing there, you are right at the problem circuit, and that could very well be why as you are working in that area, things start working again.
Check that the metal terminals haven't lost there spring tension, and look real close for any discoloration or signs of heat or melted plastic in the area of the relay and fuses.
Seems funny, that you start probing and things come back to life.
The Door lock fuse picks up it's main power from the very same location as the Engine Control Fuse.
This #8 courtesy fuse door lock fuse also powers the BCM. This fuse is in the IP fuse block.
I am going to try to locate the lug where the power is picked up for both.
Underneath the electrical center under the hood that has the EngCont Fuse in it, there are some Fusible Links. They are Wires that have rubbery insulation on them and they are designed to burn like a fuse in case of a major short. I believe that where these fusible links may not be secured tightly at where they pick up battery their voltage supply.
The one that supplys the Eng Control and the IP fuse #8 for Body Control and Door Locks will be a Gray on under this electrical center under the hood.
The Fuse Link may also stretch if the link inside of the insulation is burned part way.
Pull gently on the fuse link and you can sometimes find the problem that way.
I don't know for sure if this image is labeled correctly, but you know the one that needs to be checked.
Hope this does the trick