Jumping Starter W108 280SE 4.5 - PeachParts Mercedes-Benz Forum

galaxyjb · #1 09-08-2012, 01:39 AM

Can someone tell me Which wires to jump on the terminal block on the fender well by the alternator to get the starter to crank. Is it the big screw With the alternator wire(and others), the middle one with the purple/red wire or the screw closest to firewall with the purple wires. Do I connect a wire from the positive post on the battery to one of these to try to get the starter to spin when it won't engage when using the key in the start position?

I am still working on figuring out why my 280 won't crank, the intermitent issue, diss used in pervious post, link below, has now become a wont crank issue. I cleaned the master relay wire and 3 screw terminal block on the fender well near the alternator. Have not changed the ignition switch or starter yet.

http://www.peachparts.com/shopforum/vintage-mercedes/313437-strange-starting-problem-72-280se-4-5-a.html#post2890950

wbain5280 · #2 09-08-2012, 08:37 AM

Typically, and I don't have a 4.5, alternator wires connect to the alternator. Look at the starter solenoid itself and there is a colored wire attached to a terminal on it, use a light. Get a voltmeter or a test light and have someone 'start' the key. There should be voltage on the terminal. if there isn't your wire may be broken inside the harness.

I had a '65 220SE back in the early 80s and that happened to me, in a parking lot, close to a hardware store. I had driven the car there and then it wouldn't start. I bought a test light, had my friend turn the key and traced the wire back to where I had voltage. Over the years, the wire had vibrated and eventually broke. I made the necessary repairs and it started. I was without tools at the time so I vowed to always carry some with me.

galaxyjb · #3 09-08-2012, 07:24 PM

Turns out the alternator screw needs to be jumped to the screw with the purple wires, which runs to the starter solenoid. The car fired right up leaving the key in position 2 while doing this which leads me to think its the neutral safety switch, ignition switch or a bad wire. Will keep the thread updated for those who have this issue in the future.

Adv_rider · #4 02-09-2013, 03:58 PM

What was the problem?

I'm experiencing similar problem.

Tomguy · #5 02-10-2013, 04:50 PM

Adv, if it's the NSS, leaving the key in "2" (DO NOT DO THIS LONG! It will fry the ignition box) and jumping the purple screw with a (+) will get it to crank (let go once it fires up). I made a DIY on this site for cleaning & calibrating the NSS.

Adv_rider · #6 02-10-2013, 09:24 PM

Quote:

Originally Posted by Tomguy

Adv, if it's the NSS, leaving the key in "2" (DO NOT DO THIS LONG! It will fry the ignition box) and jumping the purple screw with a (+) will get it to crank (let go once it fires up). I made a DIY on this site for cleaning & calibrating the NSS.

Thank you Tom, I just yesterday put ignitorI with flamethrower ( I had ignitorII but was recommended to downgrade due to solid core spark wires)..... So I'm aware of not frying it.

I am using a remote starter that I purchased at autoZone. This saved my day yesterday when it first happened...

I will check the NSS and follow your thread ... BTW Thabk you, great information.

Adv_rider · #7 02-11-2013, 12:33 AM

The rubber donut in the middle of the exhaust broke some days ago and I'm thinking the exhaust heat may be affecting the NSS..... Is this possible?

The car sit all day long today, a couple hours ago I tried and its cranking perfectly! ... I changed the distributor so I had to start it up several times and no issues.