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243 views and no response??? HELP!!!PLEASE!!

3K views 36 replies 10 participants last post by  carnut62 
#1 ·
I posted last night about trying to find the connection where my neutral safety switch was bypassed.
I have no power to my starter solenoid. My starter is good (its set up now with one of those jumper wire things that go inside the car on a trigger to start it), but i am trying to find out why i have no power to it.
My turn signals and brake lights and instrument cluster stopped working a few days ago..i checked the fuse box and the fuse looked good, so i thought maybe there was a fault in the fuse box itself (a mechanic said a couple years ago that he thought my fuse box was faulty and i thought it caught up w/me). Soooooo....i pulled the fuse box and installed a new one, being VERY careful to document precisely where every wire went. Everything went perfect, and i also installed a new instrument cluster. That went well too. When i went to start the car though, i had no response from the starter!!!!! Checked for power at the solenoid, and nothing!! I have been having a problem with continuous charging loss from the battery which i have been trying to track down, to no avail, so i charged the battery fully (13.7 volts), and still nothing. My ignition assembly has never given me problems (and am hoping it still isnt), and i was thinking maybe i knock a wire loose under the dash that is preventing power to starter solenoid) when i was r/i instrument cluster???? Only thing i can think is that i messed up the bypass on the NSS that was done when the car was converted to manual from auto some years ago. But i dont know where to find that bypass, etc. I looked under the dash, to the right of the accelerator area, but dont see anything...

Will some of you all-knowing benz genius' PLEEEAAASE help me out???? Single mom, 4 kids, daily driver, missed 2 days work already, and a weekend on this....Thanks!!!!!!!

'79 300td diesel
 
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#3 ·
I don't know if the 1979 mercedes has the Connector in the same place?
On US Cars of My Year and Model to the upper right of where your Foot rests on the Accelerator Pedal there is an Electrical Connector. The Violet/Purple Wires on the Connector go to the Neutral Safety Switch.
The other Wires in the Connector go to the Backup Lights.
There is pictures in the below thread of mine.
Neutral Safety Switch Troubleshooting 84 300D - PeachParts Mercedes ShopForum
 
#5 ·
Sorry to hear of the grief that this is causing you. Not to rub it in, but I have always said that these cars should not be an only car because of problems like this.

Don't feel snubbed by the lack of responses. Your situation is one of a kind and no one has any knowledge of it.

When you say NSS bypass, will the car normally start in any selector position? Some posts tell of non-starting issues only to find the selector in a drive position (Not in park).

A fully charged battery is closer to 14.4 volts.

Do you have a multimeter?



I don't have any experience with your specific issue but here are some general troubleshooting tips.

STAR TekInfo has online manuals including wiring diagrams.

Fuses can be bad even though they look fine. I have seen a hole corroded in the point end of the fuse causing it not to flow electricity. Roll the fuses in their holders to help with good seating. The factory aluminum fuses should be replaced with brass and copper fuses. Try to find ones with ceramic bodies rather than plastic.

Unseat connectors and inspect for cleanliness and and tightness. The sockets can spread open and not grip. The best way to test for tightness is to use a pin from the other side of the connector. It should move with a slight drag. If you don't have a spare pin, get a drill bit as close to the pin size as you can find. Go under rather than over it the exact size cannot be found. Remove any sharp edges from the dull end. A Bright drill will give better feel.
 
#6 ·
You guys are so great.

This is what i found...

The bracket for the NSS is there, but no connector whatsoever. The PO x2 must have wired it another way.

I traced the purple wire from the solenoid thru the firewall below battery, back behind glove box, under windshield/over console, and have now determined that i have to pull instrument display again, to trace further...ahhhhhhh!!!!!!! I can only assume that i disturbed whatever when doing this before, or removing fuse box. I also traced the purple wire from the glow plug relay...it ran thru firewall under fuse box, and plugged into an electrical pin connector, which picked up wire and took it thru harness to ignition assembly.

Do i sound like im doing this right?

Thanks again for all the good info from everyone...u guys make it possible for us amateur to own one of these cars. I love my car, sigh.
 
#7 ·
And car has been converted to manual, no park, will start in any position if i push in clutch, except neutral, which will start either way.

Battery has a drain somewhere (next on list), but was fully charged, or at least enough to turn over. We also had battery hooked up for jump when we got nothing with starter. Check power to solenoid, and nothing there...assuming a break in line from ignition assembly, unless someone knows of something else? Ignition assembly has never given a problem before this.
 
#15 ·
This thread is getting out of control

Can you say whether the car has a manual gearbox or an automatic transmission

And car has been converted to manual, no park, will start in any position if i push in clutch, except neutral, which will start either way.

Battery has a drain somewhere (next on list), but was fully charged, or at least enough to turn over. We also had battery hooked up for jump when we got nothing with starter. Check power to solenoid, and nothing there...assuming a break in line from ignition assembly, unless someone knows of something else? Ignition assembly has never given a problem before this.
Can you run a jumper lead between the solenoid and the battery and get the starter motor to work?

ok...so i am thinking that i have an ignition switch problem that is causing me all these electrical problems, and my starting and battery drain problems.

does this sound possible?
i dont have any problem with the tumbler, but i noticed oil around the pin/switch part on back of ignition assembly...i think i read somewhere that this is from vacuum something or other...would this cause malfunction/shorting in electrical system?

any help is great! im on day 5 of trying to track down my problem!
You give me the impression of someone rushing about like a headless chicken - calm down and consider things in a logical focused order.

Present information you wish to share here in small concise lumps of information. (This is referring more to your first post)

Use white space between your lumps of information!

Oil leaking behind the dash comes from the oil pressure gauge - it is most likely to be a direct pressure gauge with a tube (not electrical) running from the oil filter housing.
 
#8 ·
The connector on a 79 car, is near the transmission under the car. The early years didn't have that connector by the hump.

No idea if this would still be the caused now, or if another problem may have been created. I would have looked at that connector and then eventually move to the ignition switch. With an issue like this, you really need a voltmeter.
 
#10 ·
I have an ohmeter (that shows volts)...i have been using that. I will have to look under car tomorrow to check if some kind of connection exists for where the NSS would have been.

What is the kick down switch? The small square block under accelerator pedal?

I traced the wire as far as the drivers side, under dash panel, near fuse box, where it disappears into a clusterfu*k of wiring harness nightmare....ahhhhhhhhhhh! Sob, sob...no voltage in wire from starter solenoid to this point, with key turned to max position.

I DO have voltage in same purple wire from back of ignition assembly to glow plug relay on inner front fender of car on driver side.

Any ideas? Please, please, please????
 
#12 ·
Indeed - I estimate a division of the number of views by 100 gives a better idea of who in reality has clicked on your thread (when it is below 500 hits)
 
#14 ·
i dont have any problem with the tumbler, but i noticed oil around the pin/switch part on back of ignition assembly...i think i read somewhere that this is from vacuum something or other...would this cause malfunction/shorting in electrical system?

any help is great! im on day 5 of trying to track down my problem!
 
#16 ·
the car was converted to manual...5 spd w/ reverse.

the starter works fine with power to it...but right now the purple wire that comes from soleniod has no power. I have a trigger that i push inside the car to jump the 2 posts on the starter/ solenoid to fire her up.

the oil is not coming from the oil pressure guage behind instrument cluster...it is seeping out of pin area of ignition switch assembly.


the battery becomes drained when i use the lights, wipers, turn signals ( especially at night) ...if i turn off all electrical accessories and let it run about 1/2 hr, i can start her back up without charging battery.

i just had the alternator replaced, but still not charging battery properly.


sorry... i FEEL like a chicken with its head cut off!!

i am ready to ship her to u and have you take her to bits... :)
 
#18 ·
the car was converted to manual...5 spd w/ reverse.

...
Great stuff

...

the starter works fine with power to it...but right now the purple wire that comes from soleniod has no power. I have a trigger that i push inside the car to jump the 2 posts on the starter/ solenoid to fire her up.

...
Fantastic!

...

the oil is not coming from the oil pressure guage behind instrument cluster...it is seeping out of pin area of ignition switch assembly.

...
In which case you should be able to see oil in the clear lines running from the vacuum pump and the brake booster. If there is oil on one side of the check valve and not the other then say which side!

...
the battery becomes drained when i use the lights, wipers, turn signals ( especially at night) ...if i turn off all electrical accessories and let it run about 1/2 hr, i can start her back up without charging battery.

i just had the alternator replaced, but still not charging battery properly.

...
This does sound like the battery isn't being charged by the alternator - even though you have changed it for another.

Do you have a multimeter?

...
sorry... i FEEL like a chicken with its head cut off!!

...
I know the feeling too - it is always different when it is your car with the trouble - giving advice to someone else is much easier.

...
i am ready to ship her to u and have you take her to bits... :)
Oh great - I'll enjoy that!
 
#19 ·
Oil in the ignition is most likely a failing/ed fuel shut off device located on the injection pump. Should be a brown/violet hard vac line going to a rubber connection on the device, pull that line, you'll find oil. Replace that device, it has a diaphragm that has failed and allows engine oil to be sent to the ignition switch.

You have an unusual set up, so I can only help so much.

Good luck and keep us posted.

You mention the battery doesn't get properly charged. If you have a drain on it when using anything, that makes sense. Does the battery light on the dash light up when you engage the key to position 2? If not, the alternator needs replacing, at least that cured my similar issue. Yet you have a "new" alt., so perhaps the wiring isn't correct.
 

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#20 · (Edited)
nutz 4 benz
i not aware of any alarm on it, except the buzzer when i open the door and the key is in ignition and/or
the lights are left on


stretch
i will check this weekend for oil in those clear lines. i am away from the car for 2 days, working. Was
able to borrow a car for a limited time...YAY

i checked voltage from battery before/during running car to check alternator...definately not charging
much, if at all...about 12.76 before, and 12.9 during, even with revving engine. @#$%^

(following your threads on ur cars...omg, so much work! and good work! i am so afraid to pull any trim, etc
because of what i will find. anyway, i have to get this girl running okay first)

rmac58
good info! i will check the part on the injection pump this weekend also...where do i find the pump? any
pics, so i know what it looks like? maybe i can google it...


Note: When i touched light meter end to purple wire under dash (which i traced from solenoid), it had no power...but there was a completely new, loud buzzing sound from center console area. This only occurs when i touch the purple wire with a grounded light meter?????????????
 
#23 ·
The vacuum pump is located on the other end of the main vac line going to the brake booster.

Maybe your voltage regulator needs replacing, but being a "new" unit, should be fine. You can remove the two screws holding it in place, remove and inspect the length of the brushes. It is located on the back of the alternator, accessed from under the car. I use an offset screw driver.
Where did you get that alternator?

From a distance, not sure just where any wiring issue would be. I assume the alternator plugs into the car's wiring harness without any extra orifices. The light comes on, so that should make a complete connection. If it stays on, that suggests a failing voltage regulator.

When I replaced the shut off device under hood, I also had oil getting to the ignition switch. I used brake cleaner spray from the shut off device, valve, I think is what MB calls it, placing a small bucket under the end at the ignition switch, cleaned out that line, let dry and reinstalled everything. In my case the ignition switch itself was none the worse for wear.
 
#24 ·
rmac58

will i be looking for the main vacuum pump (i know where that is, my check valve broke and i had to get a new one), or the injection pump? for the shut off that is leaking oil to ignition?

The alternator was changed by a mechanic who was happy to switch any part he could and charge me big money, while only half assed fixing things. I am sooooooooooooooo pissssssssssssed about the whole thing...i TOLD him that i thought it only needed a regulator, and he still changed the whole thing. I dont know what piece of sh!t thing he put in. Will have to check, sigh.

Alternator plugs in normal way...do these things need added ground, or do they ground themselves through installation...thought i read somewhere about some people adding grounds to them.

what are the things i should look for in a bad switch?
 
#29 ·
The shut off valve is located on the IP, see pics. It has a brown/violet line going from it to the ignition switch. That valve, not a pump, has the failed diaphragm I referred to earlier.

Sounds as if you may need another alt. The plugs are complete, no need to add a ground.

You certainly need a new mechanic!

If possible, work on your car yourself. There is a great deal of an accomplishment feeling when you learn something and fix your own issue.

Not sure what switch you're referring to.
 

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#25 ·
In order for an alternator to charge, it must have voltage to it. Probe the thicker wire on the alternator harness for the presence of voltage. Oil in an ignition switch will NOT harm it. Your receipt should show the alternator part number if it was replaced and there better be a warranty on it. I would assume the charging system was checked prior to replacing and re tested after????
 
#26 ·
ok, i will check voltage to alternator, too...

i had thought that maybe the oil inside the pins might have conducted electricity, and shorted something out...maybe its not my ignition switch...how can i tell? i have power in the lines to it that run from the glow plug relay...where does the power come out of it to solenoid to test them?

The "take it all out, and throw it all in" mechanic would have tested the alternator, i ASSuME...and i"m at a stand still with him, cause i refuse to pay the last bill of $568 he sent me (although he hasnt even called me about it after 4 months)...i sent the car back to have him finish up work he had charged me for before and not finished, and he billed me again. #@$%&* him.
Anyway, i will check the receipt.

another note: i have power to my windshield wiper motor, but the combination switch wont activate them...however, the turn signals work, and high beam works.
would the combination switch short out other functions, or draw power from my battery? i think its connected
to the ignition switch?
 
#28 ·
i will check power to alternator saturday when i get home.

i picked the car up from the shop on a saturday when they werent open...he left the keys for me. i really dont think that he expects payment...he was the one who put the shock on my car that came thru my floor in the rear...which, btw, he then charged me to replace.
 
#30 ·
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