Aftermarket alarm shuts off ignition (Was: Ignition Switch failure?)

[jnes]

Moderator edit: Root cause was the alarm, not the ignition switch. Thread title updated.

My car has now left my folks several times on the road. Engine stops shuddenly without any misfires or warning lights. First time was during the driving, second time at idle on traffic lights..
When trying to start car tries to start but won't crank. Also all warning lights won't light during the re-starting the engine. Also gauges wont't work. Blinker and brake lights will illuminate and radio is working. Blower is not working also. Could it be the ignition switch which causes the problems?

I have aftermarket anti theft system installed currently and I'm also thinking that it could also cause this problem.

What are the ordinary symptoms when ignition switch fails?

I haven't read yet the fault codes but I'm workin on it.

I'll tried to search but haven't found anything so maybe you guys could help me and get my car back to road again.

Thanks

:?

 

[nocfn]

sorry your folks have this. It has been known to happen, but more familiar with the fault on the W126. For our W124, it is cheap replacement around $32 usd:

Manufacturer: Mercedes-Benz Part Number: 202-545-01-04
Part: IGNITION SWITCH
Replaces: 124-462-03-93

So not sure if it is your specific issue, but it is an item that can be a root cause to much, like the light switch. Keep us posted, be sure your switch is tightly connected and consider NSS Neutral Safety Switch. Move gear selector around, check for sloppiness of bushings. Car may not think its in park.

 

[jnes]

When last time red fautl codes NSS gave a code. I have bought new NSS and at least now it should be replaced. Thanks for tips! All information is welcome. These electrical issues are not my favorite thing.

 

[gsxr]

Start with the simple stuff first:

Check battery terminals, make sure BOTH nuts on the positive terminal are tight

Check all fuses, rotate each or better yet remove / clean the ends. Don't forget to check the four in the CAN box on the GM module (these wouldn't prevent the starter from engaging)

Check the battery to make sure it's good, need a load test. Simple/quick check is to turn the headlights on high beam and see if they are bright or not.

Based on what you describe, if the battery & fuses are good... the ignition switch is looking awfully suspicious.

 

[jnes]

Battery is replaced in last summer so I think that it isn't the problem. Thanks for the tips. I'll check the fuses ant battery terminals.

 

[Stevester 500E]

I had the same symptoms on my C36. It ended up being the crank position sensor.
Not too long after I replaced the crank position sensor, the ignition switch went faulty on me.
The car would start, but there were other issues related to the switch. I also replaced the switch.

 

[jnes]

Battery terminals an all fuses are ok. I haven't load tested the battery but I'm assuming that it is ok because it's only year old.

I don't have an access to EPC at the moment so Can someone give me a correct part number for ignition switch. Is that part number correct for my car which nocfn, gave in post #2? Car VIN is 1240361B549704.
I made few part queries for dealers and aftermarket part suppliers and their prices for ignition lock switch variables between 35 - 110 euros and they are not sure is it correct part for my car..

 

[nocfn]

here is a data card for you, and the ignition switch with the superseded p/n. either will work.

 

[jnes]

Hmm, finally have access to EPC and I search for that ignition switch. My EPC will give a part number A202 545 02 04 for that ignition switch. I have ordered A202 545 01 04 ? Any idea is those parts interchangeable? Ordered part has not yet arrived. Or have I bought the wrong part?

Then is it necessary to remove whole steering lock assembly to replace ignition switch? Should I also take instrument cluster out for having more space to work with?

 

[gsxr]

My EPC will give a part number A202 545 02 04 for that ignition switch. I have ordered A202 545 01 04 ?

Based on your VIN, your car needs the early switch (to chassis B563785) which is p/n 202-545-02-04 .

Late chassis (as of chassis B563786) uses p/n 202-545-01-04.

If your chassis is B549704 then it appears you have ordered the wrong switch.

 

[jnes]

Okay, Finally had time to change ignition switch. No improvement. Fuel pumps won't work, also diagnostic pin has no voltage. So I'm assuming that LH, EZL and ASR boxes has no voltage at all. I took off the computers and measured pins between BM and LH and diagnostic socket. Only minor voltage noticed between these. Am I right that there should be +12V between pin 26 at LH unit and pin 12 at BM and also in diagnostic socket pin 3 ?

 

[lowman]

ive replied to your message.

 

[jnes]

Yeaah, finally engine started Issue was old aftermarket alarm system. I'm so happy now. Only have to assemble dashboard etc.