w124 E320 Wagon mysterious no start (no crank at all)

[Dbreid]

All,
This one has me a bit stumped. I have a 1995 E320 Wagon (used to be owned by folks on this board, Dave, Gerry, and Ken) in generally excellent shape. I have been using it as a daily driver for a long time now, and it has always been dead reliable. Sunday night, I pulled it in the garage, and when I went out Monday morning to start it... nothing.

Symptoms:
Put the Key in, hear the fuel pump kick on, all the dash lights come on normally, buzzers buzz, and when you turn the key... nothing. Acts like a Neutral Safety Switch issue... but more on that in a sec.

Things I have tried/eliminated

1.) The battery is good, and strong. It has an Odyssey (1 year old), and I put a charger and a jumper on it for good measure, and it measures fine. Plus, there's no solenoid clicking like you'd expect from a weak battery.
2.) I tried to start it in Neutral, and by wiggling the shifter about. Nothing. Doesn't start in Neutral or in Park. Also, in every other car I have had where the NSS failed, it gave sort of a warning, like started to flake.
3.) I figured it was the K38 relay. So I pulled the cluster, and figured I'd have to jumper the wires. And lo and behold (not even sure why I bothered) Dave/Gerry/Ken had already jumpered it, and that didn't bear any fruit.

The starter mechanism in this car is by no means complex, so it is odd that it would fail so suddenly and weirdly.

Any advice on where to start? Is there a way to bypass the NSS without getting under the car? Unfortunately, it is in a garage bay that makes it a little hard for me to jack it up and get under it easily.

-Dan

 

[gsxr]

Dan, can you bypass everything and try to force the starter to engage (with the key/ignition off)? Find the 3-pole connector shown in the photo below - note this only applies to non-V8 models (the V8 have it in a different location). If you send +12v via a healthy-size cable to the center position, it should engage the starter solenoid and crank the engine. If the starter still doesn't engage, I'd suspect the starter/solenoid assembly.

If it cranks over normally, something is awry between the ignition switch and starter. Oh - also check all fuses. One of them (forget which) can cause a no-crank scenario. You can fabricate something similar to the test cable, also shown below... I hooked that up to a generic hand-held remote starter button (like this). Normally this is done for compression testing, but it also lets you determine if the starter is good, when it isn't working from the key!

 

[Dbreid]

Dave, Excellent.

Just tried that (I defined "healthy" as 14 gauge stranded copper wire) and it cranked immediately like crazy. So it isn't the starter.

Next to go re-check all the fuses. I have been a good boy and replaced them all with the good copper ones, but maybe something is amiss.

 

[Dbreid]

Maybe I am missing something, but all the fuses seem fine. None are blown, and I twisted them all, and none seems to be amiss (and car still no love).

 

[Stevester 500E]

I had a no start condition one time on an W124 M104.
However,, I had that unique issue where half of the cluster lights were out, something like this.
I unbolted and thoroughly cleaned the connections and contact points in the areas circled in the snippet below.
I think I used a razor blade and fine sand paper. You have to unplug the battery and be diligent about scraping/sanding both sides off all contacts I point out below, etc.

Not that this will cure your issue, but it is worth a try and it is an ounce of prevention, at any rate.

 

[Dbreid]

I am now feeling sorta like it has to be a blown NSS. Is there a way to bypass that, so I can start the car and drive it elsewhere to work on replacing the NSS? Or can I fake it by turning the key and jumpering the starter at the same time? That seems a little on the dangerous side?

 

[gerryvz]

I was going to suggest that three-pole connector underhood on the driver's side as well. I had used that same method in the past to test things.

I also believe from what you are saying that the NSS has failed. It's really the only remaining single point of failure that controls current to the starter, other than the ignition switch.

The NSS on that car has been replaced numerous times (the starter was also replaced by me). I did it at least two -- if not three -- times. Sometimes a couple of years apart. For some reason the 6-cylinder cars' NSSs seem to fail with regularity. I would not in the least be surprised if that is the issue. Unfortunately you have to jack up the car and get under it to do this work. It can be done in the driveway, and is not too horrible of a job. The six-cylinder cars have a smidge more room to work than the 8-cylinder cars do. There's a HOW-TO on doing this job, so check it out carefully!

Get the factory NSS, not an aftermarket one if you see one available. They are not too horribly expensive. My G-wagen takes the same one as the E320, and I keep a factory spare on hand for the eventuality of it failing.

Cheers,
Gerry

 

[kwontumspeed]

An easy test for the NSS: X49/2 by the gas pedal. Jump the purple/purple white stripe. This takes NSS out of the equation. If it still doesn't start, it's probably your ignition switch (google X49/2 with relatable words for the W124 and you'll find plenty of images of location and appearance)

 

[slow_3.2L]

I am now feeling sorta like it has to be a blown NSS. Is there a way to bypass that, so I can start the car and drive it elsewhere to work on replacing the NSS? Or can I fake it by turning the key and jumpering the starter at the same time? That seems a little on the dangerous side?

Sorry to revive this old thread, but I have the same symptoms. Did you ever figure it out?

I'm torn between a neutral safety switch and an ignition switch; it seems less likely to start after being driven or when it's really hot outside. It's intermittent for me, and I can always start the car with the aftermarket Clifford remote starter.

In my case, it's the only way it always starts when this issue happens intermittently. I also jumpered the K38 relay and bypassed the original alarm a long time ago. I'll try to perform the NSS test, but are any of those parts "heat sensitive" or likely to fail after the car is warm?

 

[woodman]

Sorry to revive this old thread, but I have the same symptoms. Did you ever figure it out?

I'm torn between a neutral safety switch and an ignition switch; it seems less likely to start after being driven or when it's really hot outside. It's intermittent for me, and I can always start the car with the aftermarket Clifford remote starter.

In my case, it's the only way it always starts when this issue happens intermittently. I also jumpered the K38 relay and bypassed the original alarm a long time ago. I'll try to perform the NSS test, but are any of those parts "heat sensitive" or likely to fail after the car is warm?

If you need a new ignition switch buy MBZ only. Bought a aftermarket once and it didn’t even work. Not fun to do twice !