There's two styles of solenoids. On newer vehicles they used the round solenoid as a relay to switch the much lower solenoid current to the starter. If you have only the fat battery cable on the starter, they're using the solenoid as the switching device for the actual starter current. In other words, they're using the solenoid as a solenoid, not as a relay. The starter should also have a tapered cover.
There's two smaller terminals on the solenoid. One gets 12 volts from the ignition switch when it's in the "crank" position. The second one is the problem. The engineers couldn't agree on what to use that one for. This is where it's real easy to get the wrong part. Does the solenoid click loudly when you try to crank the engine? I'm guessing it doesn't. First try moving the smaller red / blue wire to the other small terminal. Was there a second smaller wire on that second terminal?
On older vehicles that second terminal also got 12 volts switched onto it during cranking. That was for an ignition resistor bypass to produce a hotter spark to aid starting. That terminal is not needed on most fuel injected engines. One of the coils of wire that activate this style connects between the small terminal and the metal rear cover, so the solenoid has to be bolted solidly to the body to work. The voltage coming from the ignition switch goes through the neutral safety switch first, then, if you're in "park", it shows up on the red / blue wire.
One the next style, the voltage on the small terminal comes right from the ignition switch, then the second small terminal has to be grounded through the neutral safety switch. The same thing is done with the clutch switch, when used, on a manual transmission.
If the solenoid is not clicking, to avoid overlooking some other problem, use a jumper wire to connect the battery positive post to the smaller solenoid terminals. Try it on one first, then the other one. If either one makes it click, that's where the red / blue wire goes. If neither one makes it click, use that jumper to apply 12 volts to one of them, then measure on the other one to see if 12 volts appears there. If it does, one of those two has to be grounded.
Next, check for voltage on the red / blue wire. To help me know which circuit you have, use a helper to work the clutch pedal and ignition switch unless you can prop up the test light to see it. Turn the ignition switch to "crank", then push the clutch pedal down. When does the test light light up? Does the clutch pedal have to be pushed?
Friday, February 7th, 2014 AT 8:59 PM