Author Topic: W108 M130 starter relay or ignition switch W11x (Read 4322 times)

bracurrie · « **on:** October 03, 2021, 15:11:39 »

Intermittently my M130 powered W108 with manual column shift will not engage the starter when I turn the ignition key. Starter is newish and confirmed good. All electrical connections are confirmed and the starter engages using the junction block. I've been told that relays either work or don't.
Thoughts?
Brad

ja17 · « **Reply #1 on:** October 04, 2021, 05:53:22 »

There are no starter relays on your car. The main relay is the starter solenoid itself. It could be the neutral safety switch, it's cable or adjustment depending on the year of your car? Two different automatics were used in the W108s depending on the year. More information needed.

bracurrie · « **Reply #2 on:** October 05, 2021, 14:25:05 »

Quote from: ja17 on October 04, 2021, 05:53:22

There are no starter relays on your car.

Thanks Joe. Its a manual shift car. According to Service Manual (assuming I am reading it correctly) the relay is located passenger side near firewall. Part # from picture is 0 332 202 001 and I've been told new number is 000-542-59-19.
Still waiting for another failure event.
Brad

Fonzi · « **Reply #3 on:** October 06, 2021, 13:01:47 »

Is there a neutral safety switch on this setup? I understand a floor shift manual does not have one, but don’t know about the column shift ones.

bracurrie · « **Reply #4 on:** October 06, 2021, 13:51:35 »

There is no NSS. I can engage the starter in gear. I've done it once or twice inadvertently.

bracurrie · « **Reply #5 on:** October 06, 2021, 14:06:28 »

The other day when replying to Joe, I couldn't find where in the BBB I found the reference to a starter relay.
But I found it this AM. See attached PDF

Pawel66 · « **Reply #6 on:** October 06, 2021, 15:46:39 »

Sorry, what starter relay? There is no starter relay on these cars, I think. What would this starter relay be activating?

There is no reference to starter relay in the pdf attached (difficult to read, you need to copy the text to a word or ppt document).

wwheeler · « **Reply #7 on:** October 06, 2021, 17:55:40 »

The relay pictured I believe is the 5 post Bosch relay and is typically used for power windows or emission devices. I have (2) 5 post relays and (4) 4 post relays on my ‘68 W111. None of them are for a starter relay. Pretty sure as has been stated, these cars don’t have a starter relay.

bracurrie · « **Reply #8 on:** October 08, 2021, 15:41:33 »

Upon more careful reading of the Service Manual, it appears the relay in question is to ensure the clutch on the AC compressor isn't engaged when the starter is engaged trying to start the car.
So then this non-trained limited experience fixing these things question is: Will this relay prevent the starter from engaging?

lpeterssen · « **Reply #9 on:** October 08, 2021, 21:40:21 »

Dear bracurie

That relay with 5 prongs is what is called a change over relay on the electrical wiring diagrams for the AC conditioning system.

It uses the signal given by the ignition switch terminal T50 just to disconnect the A/C system during the cranking.

This relay will not affect in any way the operation of the starter (starter selenoid).

Your problem, as you already indicated that the starter engages when a positive signal is given directly to its port T50, is ONLY RELATED TO THE IGNITION TUMBLER SWITCH.

That part is defective, since internally has accumulated many dust, and the contacts on CRANK position are not doing its job.

Change the ignition tumbler switch or run a positive cable with an external push button to the port T50 at the back of the ignition tumbler.

Tumblers for w108 are not expensive, so better to change it.

Best regards
L.peterssen

bracurrie · « **Reply #10 on:** October 08, 2021, 23:17:00 »

Thank you. I have a replacement on the way and it is indeed reasonable. Would love to have a failure event to test.
Brad

ja17 · « **Reply #11 on:** October 11, 2021, 05:01:10 »

The starter solenoid or battery connection are most often the causes of intermittent starting problems.

bracurrie · « **Reply #12 on:** October 11, 2021, 16:40:09 »

Quote from: ja17 on October 11, 2021, 05:01:10

The starter solenoid or battery connection are most often the causes of intermittent starting problems.

You are quite right and my mechanic immediately went checked both possible causes. Both were eliminated as the cause during the last failure event. I was able to use the junction block to engage the starter with the key in position 1.

bracurrie · « **Reply #13 on:** October 17, 2021, 15:23:31 »

Well the failure event finally happened and the ignition switch is not sending out the signal to engage the starter. Ignition switch it is.
BTW My daughter is getting married this coming Saturday and has been planning things since before COVID. She had asked if she could be driven from the reception in the 280 SE. Now that I know what the intermittent non-start problem is I can now assure her that the car will be available.
I had already detailed the car and I will share before and after pictures when I get time.
Brad

lpeterssen · « **Reply #14 on:** October 18, 2021, 11:36:16 »

Dear brad

Excellent to know that you pinpointed the problem finally. Ignition switch was the culprit. Enjoy the wedding celebration

Best regards
L.peterssen

bracurrie · « **Reply #15 on:** October 20, 2021, 14:23:15 »

Pulled the ignition switch and it was burned at the engage starter position, but alas the starter still wouldn't engage after installation of new switch.
There is a junction box on the firewall above where the column shift mechanism enters the engine bay. On manual shift cars that junction box houses the reverse light and an overlay where the neutral safety switch would come in if this was an automatic. That junction was loose enough to cause intermittent failure and once re-soldered cleaned up and re-seated fixed the problem.
Special shout out to Joe Alexander for the conversation that led to the discovery.
Brad

Pawel66 · « **Reply #16 on:** October 20, 2021, 14:24:25 »

So you got it all right for the wedding, right?

bracurrie · « **Reply #17 on:** October 20, 2021, 15:21:09 »

Patel,
Assuming nothing else comes up, we are go for wedding.
Brad

Pawel66 · « **Reply #18 on:** October 20, 2021, 16:31:08 »

That is the most important thing here!

All the best for the young couple!

bracurrie · « **Reply #19 on:** October 20, 2021, 21:28:09 »

In case anyone else needs to know I have attached a photo of the culprit.

lpeterssen · « **Reply #20 on:** October 21, 2021, 11:07:32 »

Excellent.

A new study case. Good to know that manual transmission cars of that year had a junction box where the T50 has a bridge on the same loom. Where an automatic transmission car has the neutral/parking safety switch.

Best regards
L.peterssen

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Author Topic: W108 M130 starter relay or ignition switch W11x (Read 4322 times)

Fonzi