biker1bmw

Starter/Solenoid Wiring

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I broke the cardinal rule and did not label my solenoid leads when i pulled my old bosch starter and now i'm trying to reconnect the leads up.  First, my 75' 02 non tii was not starting every time, it would start fine when cold but then it would crank very slowly and not start untill i ran the battery down,  had a local shop check charging system and they said starter was hanging up and causing the battery to drain after several attempts to start car.  what a pain to remove the old starter,  finally got it out cleaned up the support bracket and grounding leads,  Note:  i purchased a reman bosch unit from my local autozone for about $60 with core,  not bad,  anyway the new starter wasn't lining up with mounting holes in bell housing, found new starter had a round metal nub on front of outer housing,  my old one did not,  i took a pair of plyers and it just twisted off housing, it was not connected to anything or had any wires connected, still not sure of it's purpose but i plugged hole with a rubber plug in my stash,  ok now starter lines up great and is installed,  i attached the pos cable to the start terminal on the solenoid, but now i have 3 male spade terminals to attach my other wires to, i have tried all different possible connections but all i can get out of the starter is to get it spinning when i turn on the ignition, it does not want to engage the flywheel,  does anybody have a good diagram to help me bring this starter to life?  any help would be greatly appreciated, i do have a clymers manual with electrial schematics but they are useless.

 

I have three leads i need to connect, it's hard to tell but i think they are colored red or brown with a blue tracer, and the main lead from the altenator harness which are green with black tracer and a black with green tracer or it could be yellow.

rookie mistake :(


thanks, Joel

Edited by biker1bmw
added more text

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I may not be the best person to help you, as I dont have a US vehicle, but here goes;

 

Wiring diagram showing the relevant components;

02 US '75 Starter Wiring horz.jpg

 

A close up of the starter with the relevant pins annotated to ISO standards;

 

02 US '75 Starter Wiring 3.jpeg

 

A close-up of an actual starter solenoid;

Revised 02 Starter terminals etc.JPG

 

 

 

Edited by JohnH
New solenoid pic

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Thanks John for the reply and pics,I will check connections and see if I have everything wired correctly im thinking I may have a bad out of box starter

 

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I think you will find looking at other BMW starters and Bosch, the terminals are also numbered the same for the same functions.  A standard for them just like wire color coding.

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If upgrading to an SR440X, what does one do with the wire that normally goes to terminal 15a?  If the car does not have a relay bypass for the ballast resistor, do you need to add one?  Sorry, this is a bit off-topic to the original question.

 

I am also confused by the description above of Terminal 50 as "To Starter Relay".  I am not seeing a starter relay in the wiring schematic for a '76 car.

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The Starter Relay is only used for automatics otherwise terminal 50 is connected to the ignition switch.

 

I dont think changing the starter would have any effect on the wiring or have anything to do with the coils ballast resister.

 

 

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1 minute ago, JohnH said:

The Starter Relay is only used for automatics otherwise terminal 50 is connected to the ignition switch.

 

I dont think changing the starter would have any effect on the wiring or have anything to do with the coils ballast resister.

 

 

Hi John,

 

Thanks for confirming the relay.

 

Per the schematic, on a stock starter, the coil gets directly connected to battery positive while cranking via 15a.  This bypasses the resistor, which I assume is done because battery voltage will droop during cranking.  Once the starter stops cranking, the bypass is removed, allowing the resistor to come into play once again.  With the SR440X, that battery connection is not present (goes to ground instead).  It would seem that the 15a wire has nothing to connect to, now.  If you do connect the 15a wire to that terminal on the SR440X, wouldn't it ground the coil and prevent starting?

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Here is the solenoid on my replacement starter, which is like the SR440X.  [ EDIT: to clarify - it is the new type of SR71X, small body like the 440/441's ]. I think the 15a wire goes to terminal 30h, but I haven't got my engine back in to try it yet.  An external strap connects the post that has the braided wire to the starter motor (this post is not labeled) to post 30h.  When the solenoid is energized via terminal 50, the positive input on 30 is connected directly to the output post with the braided wire.   So I think it is correct.

 

H

20160708_202911-001.jpg

Edited by harold
Updated with starte model number

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Hi Harold,

Right you are, and I stand corrected.  I had assumed that the SR440X and SR441X had identical solenoids, but perhaps not.  From Scott's post, where he found that the terminal connected to ground on the 441X, I assumed that the 440X would have the same issue:

However, on the 440X, the orientation of the connections stays the same as stock, that is, trigger on the lower terminal and coil lead to the upper terminal (30h)

 

Thanks for pointing this out, and John, sorry about my error.  Attached is the page from the e32 ETM showing the starter.

Pages from 1990 BMW 735i - 735il - 750il Electrical Troubleshooting Manual.pdf

Edited by Healey3000

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7 hours ago, JohnH said:

I just tweaked the solenoid picture

Nice!  What are 45 and 45a from?  The 441X?

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13 hours ago, Healey3000 said:

Nice!  What are 45 and 45a from?  The 441X?

 

According to the Bosch Automotive Handbook 2nd published 9/86 the 30h terminal designation shown on your pdf  and harolds picture is no longer current and has been replaced by 45 and/or 45a.

 

img20160710_04530683.jpg

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