Quote:
Originally Posted by ARINUTS
So , this 1983 W123 euro 300d non turbo doesn't have a junction box. and the starter doesn't get a signal when the key is turned. The starter is good and using a Jumper wire from the battery to the solenoid signal terminal, the starter turns and the car starts. Here is the best part: when you do turn the key, you hear the Glow plug relay "pong" a.k.a click off. so the "purple wire " gets the signal from the key. I need to replace that White signal wire. but no junction box is really making things difficult. Anyone know what to do?
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You should not assume there is an open connection quite yet. You may be getting some voltage though to the activation terminal. Then either your solinoid has grown very tired and wants to see more voltage on that line than is present or oxidized connections are present.
It is quite common in fact usually normal for the solinoid trigger point to be lower in voltage than the general battery voltage. Manufactures save a little money by using a less than desirable wiring size assuming the solinoid or anything in the circuit is never going to age and require more potential to activate. Just like when you used a direct temporary wire it did get a full 12 volts or very close. . So measure the voltage present at that starter terminal if any with a meter. With the key in the start position obviously.
Do put your negative meter probe to the negative terminal of the battery . If you have a ground issue the meter might read less if you put the probe to the valve cover instead for example. Only after then then put the negative probe to the valve cover to verify the grounds are good. . If so the voltage reading obtained should be identical to the last reading using the negative battery terminal.
Again I suspect the grounds are probably at least fair as the starter did roll well with the jumper. It just never hurts to check for the time involved in my opinion. After doing this type of proceedure once it takes only a minute in the future to duplicate the test on the same car or another in the future.
If say nine volts is present with the key turned to the start position. You find out in the archives if that is substandard or average. If average there are two choices. Pull the starter and repair/replace it or wire a ford starter relay positioned on the interior fender to supply a higher voltage.
Now there is even a step before that. A tired ground between the battery and car body or from the body to the transmission might be semi involved. Either clean them. Or for a temporary test establish a solid ground test connection. This is done using a good booster cable from the negative battery terminal to the engine at a place you are sure the clamp is connecting ground electrically.
I know your battery is okay as when you bypassed the trigger circuit the starter preformed well. This eliminates corrosive problems at the battery terminals pretty much as well. The usual cause of many starter problems.
All the above steps are easily preformed and do verify what the actual problem is. This is all based partially because you might think that it activated with the jumper wire so logically there is no voltage at the terminal in the start position. You may have already verified that with a meter or might not have. Assuming nothing is a good approach to problems in my humble experience. Also in responding to members questions. We have no way to know your experience level and what exactly you have or have not done.
I usually try to give answers that are pretty comprehensive taking the risk that the poster knows more about what is going on than myself. If so there is no intent to sound knowledgeable or superior. In far too many cases the poster knows far more than myself. There are the few occasions this is not so. The logic better safe than sorry does apply when responding. I can only hope I recieve the same treatment when posting questions.