New engine harness, now won’t start

Joined
Jun 6, 2016
Messages
64
Location
San Antonio
After reading another thread in which they stated the neutral safety switch as their problem, I decided to check mine out. It was disgusting and had bits of the old connector broken off in it.
5A5180E1-2FA8-4F05-9B97-6BD406BA501A.jpeg


Cleaned it ip nice and got it installed back on the truck and connected.
C1EB7CFC-E237-44E8-BC09-FB11BAF360F4.jpeg


That did not fix the problem. A few things I did notice though…my reverse lights don’t work when put into reverse and also my gear indicator doesn’t light up in the cluster (aside from the D being burned out)

Also my AT temp and oil light are not illuminated when trying to start the truck (as indicated they should be in that other thread) So…what would cause these issues with the gear indicators? Bad neutral safety switch all together? It was never an issue before swapping the engine harness.
E3BF7AD6-4979-4FEB-B19D-0F1AE5616B73.png


9501C4EC-A4AC-4EEC-8FCB-FEA4D08557CC.jpeg
 

TomH

SILVER Star
Joined
May 14, 2003
Messages
1,354
Location
Seattle
Is the starter turning? If not then you are still troubleshooting the starting circuit. Did you happen to check for 12V at pin 6 of the NSS connector with key to start while you had it disconnected?
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
Is the starter turning? If not then you are still troubleshooting the starting circuit. Did you happen to check for 12V at pin 6 of the NSS connector with key to start while you had it disconnected?
I did not but perhaps tomorrow I can get some help from my gf turning the key while I check that pin
 
Joined
Jan 5, 2017
Messages
4,168
Location
Charlotte, NC & Alexandria, VA
The Christmas tree and reverse lights are fed through EC1 (the larger of the two connectors above the started). Clean that out and they'll work.
1668084897700.png
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
Checked pin 6 on the NSS with key to start and I’m getting no voltage at all. I have a new fusible link coming in today so I’ll be able to rule that out but I don’t think that’s the issue anyway.
 

TomH

SILVER Star
Joined
May 14, 2003
Messages
1,354
Location
Seattle
You can check continuity across the fusible link to see if it is good. Some have suggested this may not be reliable with the links but I don't know about that. It's pretty easy to check continuity.

You could also pull the AM1 fuse and check continuity across the pins to verify it is good.

You could check for 12V at Pin 1 on the AM1 fuse mount. If you have 12V then the fusible link is good.

You could unplug EA2 and check for 12V at pin 6. EA2 might be under the fuse box behind the battery so it may be hard to get to.

1668109576183.png


1668109608603.png


1668109768628.png
 
Joined
Dec 8, 2006
Messages
11,048
Location
New Jersey
Website
www.sdsysdesign.com
There is one connector that runs to the starter, maybe I should disconnect it and reconnect it to see.
There are 2 connections to the starter. A small push on connector (logic from the ignition switch circuit) and a bolt on terminal which is a direct connection to the battery positive terminal.
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
I tested for voltage at the AM1 relay and I’m getting 12.7 volts so the fusible link should be good, correct? I bought a new one anyway.

The only connector I disconnected from the starter is that small push on connector. I never removed the cable going to the starter
 

TomH

SILVER Star
Joined
May 14, 2003
Messages
1,354
Location
Seattle
I was betting on the fusible link. If you are getting power to the AM1 fuse then the link is good. Did you check continuity on the AM1 fuse to make sure it is good?

To be clear, when you turn the key to start the truck you get nothing - right? No starter turning? I mean, this makes sense if you don't have 12V to the NSS.

You need to keep working down the circuit. EA2 would be next but I really wouldn't expect that to be the problem.

From there is the ignition switch. You'd need to open up the dash to get to the connector to check for 12V at pin 4.

If you have 12V in at pin 4 then you need to makes sure you have 12V out at pin 1 with key turned to start.


From there you have the I13 splice and then IH1 connector. I didn't suspect IH1 until I just looked at the location. It's right where the engine harness comes in. You might want to pull the glove box and track that connector down before looking at the other things. Reverse lights run through IH1.

1668214242550.png


1668214002221.png
 
Last edited:
Joined
Feb 16, 2012
Messages
467
Can’t believe this still has not been fixed. Reading back through looks like one those solutions would work. Nice to see all the people chiming in, I make a post about an issue and I am lucky to even get a reply.
 
Joined
Apr 14, 2016
Messages
2,364
Location
Oregon
my reverse lights don’t work when put into reverse

This often means the NSS is misadjusted. It could probably also be due to filthy contacts inside.

Have you disassembled your NSS to clean it, and then adjusted its position once it's reinstalled? Cleaning it isn't hard, just watch for the small springs that push on the copper contacts. Definitely not something you want to do in your driveway on a pitch black evening.
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
Tom, thank you for your reply and detail. I will definitely check this things and work my way up the circuit.

Definitely want to thank everyone who has chimed in as well. This is always such a helpful forum and it’s very much appreciated.

Hard to believe this has been such a fiasco from a running truck(sans cylinder 6) to how thing are now ha.

And yes, to be clear, I’ve got no kick from the starter. When I turn the key, it doesn’t do anything at all but dim the clock pretty much. I’m definitely getting no power at the NSS, I just have to figure out why not and where that loss is.

Probably won’t get to touch the truck until Sunday evening or Monday which is a bummer but I will update as soon as I get a chance.
 

ppc

M Go Blue
Joined
Aug 18, 2003
Messages
3,882
Location
Nashville, TN
Sounds like failed contacts/plunger in the starter. If the clock dims that means there is a high current draw which can only be from the starter. The "No Power" at the NSS is more than likely an improper measurement, wrong pins etc.
 

landtank

Supporting Vendor
SILVER Star
Joined
Mar 27, 2003
Messages
20,658
Location
Groveland MA
Website
landtankproducts.com
And yes, to be clear, I’ve got no kick from the starter. When I turn the key, it doesn’t do anything at all but dim the clock pretty much. I
Sounds like a bad starter. If the clock is dimming when you try and start the engine you are seeing a substantial amp draw on the battery.
 
Last edited:
Joined
Dec 8, 2006
Messages
11,048
Location
New Jersey
Website
www.sdsysdesign.com
The only way you would get a substantial current draw from the starter is if the solenoid was pulling in and making contact. In this case, you would get a solid "thump" from the starter, which can easily be heard from the driver's seat. If you're getting "nothing" from the starter, then the solenoid is not pulling in.
 

TomH

SILVER Star
Joined
May 14, 2003
Messages
1,354
Location
Seattle
That did not fix the problem. A few things I did notice though…my reverse lights don’t work when put into reverse and also my gear indicator doesn’t light up in the cluster (aside from the D being burned out)

Also my AT temp and oil light are not illuminated when trying to start the truck (as indicated they should be in that other thread) So…what would cause these issues with the gear indicators? Bad neutral safety switch all together? It was never an issue before swapping the engine harness.

This is fun, which probably says something about me if I think looking through wire diagrams is fun.

Reverse lights go through IH1.
Gear indicator lights get power from the NSS which gets it's power through IH1.
A/T light gets power from IH1
Oil light I can't tell for sure because I'm not smart enough but IH1 is in the circuit.

My guess is IH1 was disconnected when the engine harness was wrestled out from under the dash and got hidden behind the new harness when it was pushed in and never reconnected.
 

landtank

Supporting Vendor
SILVER Star
Joined
Mar 27, 2003
Messages
20,658
Location
Groveland MA
Website
landtankproducts.com
The only way you would get a substantial current draw from the starter is if the solenoid was pulling in and making contact. In this case, you would get a solid "thump" from the starter, which can easily be heard from the driver's seat. If you're getting "nothing" from the starter, then the solenoid is not pulling in.
unless of course the contacts are well worn and the plunger is partially bound up. Then you wouldn't get the thump. Sticking starter plungers are a known problem.
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
I’m definitely not getting a thump or any noise from the starter at all. I’ll look at my IH1 and see if it didn’t get a good connection for some reason. It is kinda hard to get back there but I know I attempted to snap them in place haha
 
Joined
Jun 6, 2016
Messages
64
Location
San Antonio
Looking at the diagram has me a bit confused. Here it is so you understand what I’m seeing.
F0A7A3EE-A3CC-443B-B63F-E4939CDCF0B8.jpeg


If my NSS isn’t seeing any power, how are my turn signals, wipers, etc working?

I went back and disconnected all the connectors that run in through the firewall and inspected them and they seem totally fine. There are 2 white plugs and 3 grey(ecu). Is one of this white plugs the IH1?

6574B127-D568-4A5F-81F5-591076814E58.jpeg
 
Joined
Feb 16, 2012
Messages
467
I just replaced the entire engine harness due to every connector breaking when touched(but most importantly the break in the harness to injector 6. Disconnected the battery before starting and every single plug is connected and accounted for including (engine sensors, maf, ecu, trans, and O2 sensors.

CEL is rapidly flashing (27 times to be exact) and will not even attempt to crank…

Scan gauge just says “connecting” so I can’t see if there’s an engine code

EGR is deleted but was before I replaced the harness and was running fine (on 5 cylinders)
I would go through and triple check all your connections. The common denominator to me is something is not plugged in or is loose after you swapped wiring harness. My FSM for a 94 recommends checking the starter first followed by the NSS. Here is a screenshot of the FSM on the operation.
 

Users who are viewing this thread

Top Bottom