Hello,

When I first got the truck it would intermittently start by the key. I replaced the ignition switch and then it would start in neutral if you held the shifter up towards R a little. Crawled underneath and found the DTR switch "jumped" grooves. Wound up buying a new DTR switch and installed it per instructions. Now it won't start at all. I replaced the starter solenoid relay on fender. Battery was tested at parts house, no issues. Only fuse I found that was blown was for the cruise control. I swapped relays around and they all work. I found a wiring diagram online. My truck doesn't have the pats system or a chip in the key. The only thing it does is when you turn the key to start, after a couple seconds it will click on the relay under the dash. I'm not getting the 12v signal from the ignition switch, but if I put a live 12v wire to the red/light blue wire, still nothing happens. The 15amp fuse is fine. I'm not sure what's wrong. I know if I go to the DTR and cross out the tan/red wire with a live wire it cranks. The ignition switch is brand new. For some reason it's just not getting the signal to the DTR. 🤷 The only things I haven't replaced is the Starter and the Start Interrupt Relay.

 

I also have not replaced the GEM. I feel like there is a break somewhere between the fuse box in the dash and the DTR. But I can't isolate what all is on that line. The wiring harness doesn't appear to have any extra stuff attached to it or spliced into it.

I did have to replace the PCM due to the old one being water damaged.

 

I can't help you with the no-start, but if the cruise fuse was blown, you probably have a shorted disconnect switch, which is a potential fire hazard, There was a recall on it but a new improved switch is cheap.

 

Where is that located?

I still need help with the no start issue. I'm trying to get the truck to pass inspection so I can put tags on it.

 

When referencing fuses, it's a good idea to always use their reference designator along with identifying which box they're in instead of by a description. On your truck, there really isn't a "cruise fuse" but there are several fuses used by the cruise that also serve other functions. For example, fuse F13 under the dash feeds not only the brake pressure switch glc referred to, it also provides power for the brake lights. If F13 blows, you not only have no cruise but also no brake lights.

Your truck may or may not have a starter interrupt relay from the factory, depending on its options from the factory. Does it have one or not? Check the RPO relay block for one. Need to know which schematic to reference.

Time to back up a bit... The starter circuit is not particularly complicated. Sounds like you have the schematic so follow along and check the function of the circuit one section at a time.

Check to see if fuse F21 (under the dash) goes HOT IN START. If so, then the ignition switch is okay. If not, then focus on the ignition switch installation and function.

Jump down to the DTR switch. Does the dark blue/orange wire go HOT IN START? If so, everything upstream is okay and your problem is with the DTR switch, whether alignment or faulty, since you can inject power into its output lead and activate the starter. If not, then the problem is between F21 (above) and the DTR switch.

Addressing the circuit logically and "half-splitting" it allows you to determine quickly what does and does not work.

 

I'm not sure where the rpo block is to be honest. On the passenger side under the dash I don't see a relay. Ignition switch does not send out a HOT feed in start, but the switch it brand new. The neutral safety switch is not getting the HOT feed in start either. So idk what to do about it other than spend another 50$ and buy another new ignition switch. I'm at my wit's end with this truck.

 

The small fuse block where the fuse was blown doesn't even have a cover but it's in the engine compartment, driver side on the fender wall near where all the wiring harnesses connect into the cab of the truck. That's about as descriptive as I can be. The owner's manual doesn't reference that block or the block that's attached on the outside of the power distribution block. 🤷

 

Go back to this step: Check to see if fuse F21 (under the dash) goes HOT IN START. If so, then the ignition switch is okay. If not, then focus on the ignition switch installation and function. Just because a part is new does not mean it's good, installed correctly, or has the correct inputs. Assume nothing, make all measurements. No point in messing with ANYTHING downstream until the upstream portion works correctly.

Download a copy of the 1997 owner's manual, it includes the mini-fuse box under the hood. The 98 manual omitted it although that box remained in the production vehicles that year.

As for the relay box next to the power distribution box, that's an afterthought for the trailer electrical package. Many years ago, I helped do a write-up that was a sticky for years on either this forum or over on FTE. Can't find it anymore.

 

I will check that out after I get off work. I'm not really sure how to test the ignition switch. I have pulled the switch off the column and manually held the metal post into what would be the start position and still no HOT on start.

 

I bought a new ignition switch and same thing. Not HOT on start, but just like the previous ignition switch I get a click under the dash on driver side fuse box, relay 5.

 

Not related to the START function.



Did you, as previously recommended, test to see if fuse F21 is HOT IN START using either a test light or meter? Explicit answers are most useful.... vague answers are not....

 

Yes, I've tested fuse number 21 using a test light. It does NOT GET HOT on start. I also verified that my test light works by testing other various fuses.

 

Good, that clears up the test results.

Now it's time to check to see if something else that gets power from the same input power source as the START circuit works. Turn the ignition key to RUN. Do the turn signals work? If yes, then go to below. If not, check fuse F20 (ALWAYS HOT) under the hood. It's not supplying power to the ignition switch (lt green/pink wire)

Check that pin STA of the ignition switch goes HOT IN START (Red/Lt Blue wire). If not, the switch is not operating properly. Check alignment to verify it is being properly actuated when the ignition cylinder is rotated. If yes, check continuity of red/lt blue wire between switch and fuse F21.

 

Yes my turn signals are working. I have taken my test like and tested the red/light blue wire on the connector while its still connected to the ignition switch(its the only way i know how to check the STA pin) and NO HOT IN START. How do i tell if its aligned properly? I am going to check continuity on that red/pink wire.

 

I have continuity from the red/light blue wire from my ignition switch to my F21 fuse(driver side under the dash). The only wire that is NOT getting hot is the red/light blue wiring and od course the orange/grey ground wire. I have also tested the red/light blue wire for a ground to see if its being grounded out and its not. At least there is that bit of good news since it supposed to be a HOT in start. 🤷

I still am not sure how to check alignment of the ignition switch..