1997 Mercury Mountaineer starting mystery

[OregonJeff]

First, I'd like to thank all the people who have built up this incredible bank of knowledge. Thank you, and thanks in advance to anyone who tries to help me. I have a 1997 Mercury Mountaineer, V8, AWD. The other day it would not start. It seemed to be getting power, there had been no problems or starter noises. Gel optima battery, less than one year old. I was able to start it by "arcing" across the posts on the starter relay up near the battery. That seemed to fix the issue, and I assumed that the old, original, starter/solenoid had been bound up or the starter relay was bad.
A few hours later, it happened again. I put in a new starter relay. No start without arcing across the relay. I removed, cleaned, and tightened all the connections between the battery and the relay, and the various grounds. Checked battery voltage, it was good. No start without arcing. I then drove home, a long drive. On the way, the power locks went crazy! Unlocking and locking constantly. This made me think about a loose ground.
Once home,I replaced the starter/solenoid with a new one, cleaned the connections there and verified that it would start either by arcing or running a wire from the battery to the starter. Still no start from the key. I then read about the t-25 bolts under the dash on the shifter column, squeezed into there and tightened those. No start. I then replaced the neutral safety switch - quite the issue getting the correct model switch- and replaced that this morning. No start without arcing it across the starter relay, but the switch is aligned correctly, and everything shifts fine on my test drive. I read through the forums and saw the sticky about the two PCM connector "gremlin" harnesses. I opened those, inspected the pins, cleaned both sets and retightened. No start. The dash instruments react to the key, gauges respond, key turns smoothly but no no noise at all from the starter/solenoid. Only silence.
Anyone have any thoughts?
Again, thanks in advance.
Jeff

 

[C420sailor]

Check for voltage signal to the solenoid when turning the key to start. Sounds like the solenoid is likely good, but it isn’t getting the proper power to actuate it.

 

[OregonJeff]

Check for voltage signal to the solenoid when turning the key to start. Sounds like the solenoid is likely good, but it isn’t getting the proper power to actuate it.

Thanks, C420sailer. I'll break out the multimeter and start there, working backwards. I have never been good with a multimeter, this is a good time to learn.

 

[410Fortune]

So basically the little red with blue wire is the ignition switch to starter feed.
With your multimeter you simply need to see if battery power (12v+) makes it to that little red/ blue wire when the key is turned to “start”

My guess,
From what you have said, is that no power is making it to that small post

If it starts easily when you jumper the two large posts then it’s not a wiring issue with the pcm or engine etc

Here is the start system diagram for a 96 explorer

Check fuses 24 and 34 in the interior fuse panel

The anti theft relay is also suspect (if your truck has one)

The relay would be located in the auxiliary relay box which is mounted above gas pedal

 

[OregonJeff]

So basically the little red with blue wire is the ignition switch to starter feed.
With your multimeter you simply need to see if battery power (12v+) makes it to that little red/ blue wire when the key is turned to “start”

My guess,
From what you have said, is that no power is making it to that small post

If it starts easily when you jumper the two large posts then it’s not a wiring issue with the pcm or engine etc

View attachment 465338

Here is the start system diagram for a 96 explorer

Check fuses 24 and 34 in the interior fuse panel

View attachment 465339

The anti theft relay is also suspect (if your truck has one)

The relay would be located in the auxiliary relay box which is mounted above gas pedal

View attachment 465340

Wow! That is a detailed and informative response. Thank you. I will get to checking and get back with you.

 

[OregonJeff]

410Fortune,
You were correct. No voltage is getting through the starter wire to that small post.
I checked all the fuses.
I am next going to take a look at the ignition switch harness and test with my multimeter.

Jeff

 

[410Fortune]

Smart

The red w blue wire leaving the ignition switch should have battery + power when key turned to “start”

If it does then next thing to test is the stupid raps relay / anti theft relay… if your truck even has one. If it does then you can just bypass / jumper it. Nobody is going to steal your 97 explorer

Getting to this relay box is a little tricky and it’s not even shown in the 96 book which relay is which. I can help you when you get to this point

 

[Turdle]

Ignition lock broken, not turning the ignition "switch" to start.
Pull ignition lock to look right quick. Turn key to on, leave key in ignition,
Look under column for a hole with release - retaining ball. Push up on ball, pull lock out.

Post 10 below

How to: - Ignition Lock broken, How to fix lock to use original keys

Well, just when things looked better, My wife went out to start Betty and the key just turns loose feeling. It did turn the truck "on" but fails to engage starter. Will not turn off. I had to disconnect the battery. It is as if someone had jacked the switch with a screwdriver. So, which...

www.explorerforum.com

That thread has pictures. Same symptom.


Do lights and cluster dim, turn off when turning key to start?

 

[OregonJeff]

I am still working on the old girl. Had to travel to get some new MM leads that would allow me to backprobe the wiring harness on the steering column where the red/blue starting wire originates. When I turn the key, I get voltage at that point.
This leads me to believe that the issue is either a broken starter wire/bad connection somewhere in the path from that harness to the neutral safety switch and back to the starter relay solenoid OR an issue with the neutral safety switch OR as Turdle recommends a problem with the ignition lock.
It is my understanding that the theft system on this year does not prevent crank and instead prevents spark/fuel. The wiring diagram as I try to read it, doesn't show the theft system interacting with the start wire.
Tomorrow I intend to do a continuity test of the wire at various points, trying jumping across the NSS, and replace the ignition lock....and whatever else you gentleman recommend.
Thanks for all your continuing help.

 

[410Fortune]

There is no anti theft installed on a 97 really… it’s not like the chip
Key setup the 98+ had
Yours is a simple keyless entry alarm it can only disable the starter through the “anti theft” Relay as shown on the wiring diagram

You could check the neutral safety switch
Power should come into the switch when key turned to start and leave the switch when in park or neutral. This will tell you if the issue is up under the dash or up under the hood

Red with lightBlue is power in pin 1

Pink is power out to starter solenoid pin 4

Pins 1 and 4 should
Have continuity when in park or neutral

Pin 1 should have battery power + when key turned to “start”

 

[410Fortune]

Here is the “relay module”
Box which may contain the anti theft relay in question

It is up under the dash, just above the throttle pedal to the right (towards stereo)
a smooth black plastic box with a lid.. pain to access but can be done

If this is the cause of your start wire feed issues you can just bypass it with a jumper wire

Jumper pins 3 and 5

This pic which I posted earlier shows the relay box location F-4

https://www.explorerforum.com/forums/attachments/img_5643-jpeg.465340/

 

[OregonJeff]

Here is the “relay module”
Box which may contain the anti theft relay in question

It is up under the dash, just above the throttle pedal to the right (towards stereo)
a smooth black plastic box with a lid.. pain to access but can be done

If this is the cause of your start wire feed issues you can just bypass it with a jumper wire

View attachment 465384

Jumper pins 3 and 5

This pic which I posted earlier shows the relay box location F-4

https://www.explorerforum.com/forums/attachments/img_5643-jpeg.465340/

Thank you!
Getting to work now.

 

[OregonJeff]

Here is the “relay module”
Box which may contain the anti theft relay in question

It is up under the dash, just above the throttle pedal to the right (towards stereo)
a smooth black plastic box with a lid.. pain to access but can be done

If this is the cause of your start wire feed issues you can just bypass it with a jumper wire

View attachment 465384

Jumper pins 3 and 5

This pic which I posted earlier shows the relay box location F-4

https://www.explorerforum.com/forums/attachments/img_5643-jpeg.465340/

410Fortune,

I am glad I had not reassembled the steering column covers and associated plastic, and further glad that I do a lot of stretching- that box is indeed a PITA to get to. I am going to try jumping across the pins as you recommend. If that doesn't work on to the NSS.
This wonderful book that you have and are being very generous with, is that the 1997 Ford/Mercury shop manual?

Jeff

 

[410Fortune]

It is the 97 explorer wiring manual
I do lots of wiring and diagnostics on these trucks I have several years and models of wiring books from 83-2014
I get them on eBay used cheap

Like this

Pardon Our Interruption...

I swear the 95-97 explorer has more aux relay boxes then the space shuttle
They are everywhere in those years…behind the headlights under the battery tray behind the dash in the back cargo area… all over the stupid place
Luckily we don’t have to access them very often because these trucks are also built like tanks
Nothing on this forum lasts as good as a 95-97, except maybe the 91-94… they are tough trucks
As the years go on the relays get smaller the wires get shorter and they jam them into less boxes

Very handy

 

[OregonJeff]

I am still on this issue.
I will not frustrate. Frustration is the mind killer.
In addition to other replacements, I have replaced the ignition cylinder and ignition switch. Those were both old and worn, and I am going to keep this car going until I die, so no problems.
I have bridged the #3 /#5 pins in the antitheft relay. When the key is turned to start, I get power on that bride.
However, I do not get power to the start wire input on the neutral safety switch harness.
I know that in-between the two lies the starting relay in the power distribution box. I am going to get the box off it's mount, and start back probing for current and continuity at that point. Provided those are there, I will do the same thing between the output on the box and the NSS.
Does anyone know the pins to bridge if I am trying to bridge the PCM relay, relay #5, in the power distribution box?
Thanks in advance,
Jeff

 

[OregonJeff]

I have an update. I pulled the PCM relay. I am getting constant power to 3pin 30, as should be . When the key is in start, there is power to pin 87. There is is no power to pin 86 on start, as there should be.
I think this means 1 of 3 things:

• The ignition switch is either not sending power to the relay
• OR there's a break in the wire between the ignition switch and this relay
• OR there's a bad fuse between the ignition switch and this circuit.

Since I do have power at the ignition harness, and the antitheft relay I don't think it can be 1.
I guess I'll recheck fuses and wires between the ignition and the starter relay.

Let me know if anyone has any thoughts.
Relevant thoughts, anyway,
Jeff

 

[Turdle]

Yes the PCM relay is fused. As is the starter relay.

Fuse box under hood.

You did state you performed the steps in the gremlin thread yes?

 

[OregonJeff]

Yes, I did the gremlin thread steps, but I will try those again. can't hurt.
I bridged the PCM relay pin 30 to pin 87. I was unsure if the current runs directly from 87 to the NSS. That bridge didn't produce power at the NSS.
Jeff

Yes the PCM relay is fused. As is the starter relay.

Fuse box under hood.

You did state you performed the steps in the gremlin thread yes?

 

[410Fortune]

No

The pcm relay does not power the neutral safety switch

The nss is just a pass through for the starter circuit

Power comes in when key in start
Not run or acc, but start
And the power is allowed to pass through as long as the nss is in park or neutral

Then power goes on to the starter relay on the fender

The PCM relay powers up many things but the starter is not one of them

This is the entire start circuit

https://www.explorerforum.com/forums/attachments/img_5640-jpeg.465338/

 

[410Fortune]

Power is sent from ignition switch through fuse 24 into the anti theft relay

It then leaves the relay and goes directly to the neutral safety switch (aka the dtrs digital transmission range sensor)

If the truck is in p or n
Power passes through the nss and directly out to the solenoid on the fender
Into the nss is pin 4, pink wire, circuit 329
Out of the nss is pin 1, red with light blue, circuit 32

The wire does pass through the 42 pin c115 square connector on the back of your intake on its way from the trans to the fender solenoid

Pin 31, red with light blue, circuit 32