No Crank, No Start


Those Pins are labled as such. The funny thing is that they are symmetrical in that the relay would fit one way but would also fit if flipped over 180*. And the system, at this point, behaves the same way no matter which of those 2 positions the relay is sitting.[quote=“insightful, post:35, topic:108202, full:true”]
Turn the relay over. Do you see the numbers 30, 85, 86, and 87 anywhere? If so, add where those pins would go on your picture of the relay socket.


I do have a corresponding voltage response in that the 86 shows voltage when key in Start, and 87 is hot all the time. The readings I am getting are roughly 10.75v though, this may be a reduced surface charge due to the fact that when the relay is out/removed the fuel pump etc runs and draws on the battery.
I have replaced the starter with a new/rebuilt one and the condition did not change. I also had the original starter tested and it is operational; so I’ve ruled out a dysfunctional starter as the problem.


I have alligator clips attached to probes which I have sticking into the relay slots on Pos side and stuck into battery terminal on the Neg side. ,


Have you replaced the starter relay yet? Jump 87 to 30 and see if the starter cranks, if it does, the starter is good.

I am a little concerned about the lower voltage on 86 if the ignition is in start and the relay is not in the socket. This should be full battery voltage as there should be no current flow. I would look at fuse 19 under the dash. Fuses have been know to develop a hairline crack. They look good and voltage can be detected on the other side with a digital voltmeter. You won’t detect any voltage with an analog voltmeter though because analog voltmeters draw a tiny amount of current, which a cracked fuse won’t pass.

You could also have a bad contact in that security relay under the dash.

If you can get hold of an analog voltmeter, I’d suggest you use it for troubleshooting.


In the post above – further up – I believe you said this measured zero volts. Here’s what you said

“At the starter, I am getting the full 12.45V on the B, -but 0V on the S control terminal.”


One way I’ve tested that configuration is wrapping a thin AWG wire around the relay pin to provide a test point, and plugging the relay back in.


That’s what the fusible links look like on my Corolla too. Does it say on that fuse the same number of amps as the schematic for the fusible link? On my truck the fusible links are just segments of a special type of wire. But on newer cars I think they mostly use those cartridge type fuses like you have.


Yeah sorry about that, my mistake. That reading was taken while key was in Run instead of Start. The starting system is new to me and I was still learning how to test it.


If you are measuring 12+ volts on the B terminal of the starter motor and at the same time 12+ volts on the S terminal of the starter motor (with key in “start”), measuring in both cases from terminal to starter case, the starter motor should be making that rrr rrr rrr sound and cranking the engine. At the very least you should be hearing a click. Unless your starter motor is completely dead.


Ive tested the relay and the starter, both work


I just edited my previous post with more information.


That fuse has 120Amp written on the top of it. Which corresponds to the inline fuse in the diagram, but diagram has it on one of the black wires heading to the alternator, instead of part of the positive battery terminal


s trouble light would do the same. Analog meters draw a very small current. (I don’t think that is the right term. A small thingi with a 12 volt bulb on it and two probes)


The schematic you posted in post 16 of this thread is a little fuzzy on this computer-screen, but it appears to say the fusible link is 30 A. Not 120 A. Am I misreading that label?


I agree about the trouble light. It would be a lot cheaper to buy if the OP doesn’t have access to a good analog meter.

It is a right term although “small load” can also be used. The load drawn by an analog meter would be sufficient to draw down the residual voltage.

We had a transformer returned to us at the factory by a utility once. It was a large three phase with a 4 position switch on the front, H1 to coil, H2 to coil, H1 and H2 to coil and Open. With H1 to coil selected, H2 is open, but they were measuring 460 volts on H2 with 34,500 volts applied to H1 using a digital voltmeter. When we tested with an analog voltmeter, nothing was detected. The wire going from the switch to the H2 bushings was picking up an induced voltage from the coil, but being as far from the coil as it was, and not having a coiled section, the current was unmeasurable. Digital voltmeters do not load down a circuit where an analog meter does to some degree.


I’ve always considered a trouble light one of those 120 volts lights with a cage around the bulb and a long cord.



True. But my experience was where I didn’t want any loading.


When you need dead accurate readings, the digital is better because it doesn’t load the circuit. But analog meters still have their place.


For automotive work the amount of circuit loading analog meters cause isn’t usually a problem. The downside of analog meters imo is they usually aren’t quite as accurate or precise. The upside however is analog meters are better when the voltage isn’t steady, for example in measuring the voltage on the “s” terminal on a starter during cranking I prefer to do that with an analog meter as I can watch the needle to see how high it goes during its sweep.

Reminds me of an event years ago, back in the mid 1970’s. Some co-workers and I were thinking about how future cars would be designed, and we all --all of us men – decided “no question about it, all the speedometers will display a digital number for the speed”. We were all very proud of ourselves for coming up with this idea. Then one of the guys comes in to work a few days later, says he mentioned this idea to his wife, and she said “No, most drivers prefer to see the speedomet needle move up and down, easier to check the speed that way at a glance”. We all thought about it, and although ashamed to admit it, decided she was right! LOL


The large digital readout high on the dash of my Insight is much easier to read quickly than a conventional dial.