Starter solenoid current?

Is it direct activation or relay switched ? usually a solenoid like that draws upwards of 8 or 10 amps possibly more in a foulcan , doesn't the solenoid have to drive the engagement mechanism?

Something I don't know ... and can't seem to find out all that easily.

I'm trying to figure out the current draw by the starter solenoid, (not the starter motor) at terminal 50.

It's powered through the ignition switch in the Golf GTI but the 4mm wiring has me baffled. That's too much current to go through a little ignition switch if the wire is sized for current capacity.

So I assume it's sized to avoid voltage drop, which leaves me none the wiser regarding the current actually drawn by the starter solenoid.

Bernd Felsche - Innovative Reckoning, Perth, Western Australia ASCII ribbon campaign | For every complex problem there is an against HTML mail | answer that is clear, simple, and wrong. and postings | HL Mencken

Use a multimeter if you have one. The size is usually for volt drop. The actual solenoid Id imagine wouldn't draw much at all. I'd take a wild guess at 7 or 8 amps for modern cars. the cables that size as when cranking it needs the full voltage other wise it will do what you call Motor Boating. that is where the voltage drops too low to maintain the solenoid and it drops out during cranking. As your still holding the key to the start position it will re-engage as the voltage increases now the starter isn't engaged, it keeps doing this until either a contact burns out or usually the person trying to get to work takes the bus. (or its jump started of course)

Do you know that clicking sound when ya batteries very flat? that's it.

Why not put an ammeter in series?

I believe you will find there is a relay in the circuit. What year Golf is it? BTW, yes, it is a lot of current--more than one might expect.

I believe you will find there is a relay in the circuit. What year Golf is it? BTW, yes, it is a lot of current--more than one might expect. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I think that you are thinking of the starter motor current which can easily reach 300amps. He is asking about the current draw of the actual solenoid.

theres two ways of easily testing the actual draw. Use an ammeter in series (or clamp style) and test it, or use an ohmmeter to see what the resistive load is and work it out that way @ 12v.

Yep, pretty simple really.

Direct. 4mm wire from the battery to the switch and all the way back to the strater - via a couple of connections through the central electrics backplane. Madness.

It has to start. Once it gets going, the contacts of the solenoid close and the tarter current runs a holding coil in parallel with the one powered through the key switch.

Because it could fry the poor thing ... Most multimeters maxo ut at 10 Amps. I suspect that it could be 30A, if not more. Bosch book says 30 to 70A, depending on the size of the starter.

1990. There's 4mm wiring into and out of the ignition switch when I last had that part of the sah and steering column uncovered.

Current flow diagrams (two sources) draw it as direct-wired. No relay.

No, I'm thinking the solenoid, which does draw more current that most people realize.

An ohmmeter would be less accurate due to the lower resistance, and would not provide a good indication of shorted turns (assuming that is his problem...) The best testing tool is a DC clampon meter, a tool that I find invaluable when diagnosing starter problems.

>

That would explain the 4mm.

That's a hell of a current to be going through the switch, it would be very unusual for there not to be a relay?

Daryl

Most starter relays are no more 30amps so that suggests the current is less than 30amps on most cars. Not having a relay is most unusual but it is a VW. Are you trying to fix a fault, why do you need to know how much current its drawing?

Daryl

Since you ask; not unusual. They're probably counting on the current being intermittent.

As the at least 8 million vehicles of that type have exactly that same starter wiring, from 1983 to 1992. And probably another few million Jetta clones produced in China over the past 20 years with the same.

No fault. Yet. :-)

I don't think the current draw is as high as you think. I remember a common fix for starting problems due to volt drop was to fit a standard relay.

The heavier guage wiring would be to reduce volt drop, not for high current draw.

That was a common fix on many older Toyota's, I've even fitted a couple myself for the same reason.

Most likely spot on.

Daryl

Because it could fry the poor thing ... Most multimeters maxo ut at 10 Amps. I suspect that it could be 30A, if not more. Bosch book says 30 to 70A, depending on the size of the starter.

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I'd be VERY surprised if it was over 10 Amps to be honest. a 4 mm2 cable. Seeing as a 4mm cable is really only capable of 30 Amps for a reasonably short time.

Id be testing with an ammeter. 90% of ammeters have internal fuses protecting the device anyway.

Scotty

No, I'm thinking the solenoid, which does draw more current that most people realize.

An ohmmeter would be less accurate due to the lower resistance, and would not provide a good indication of shorted turns (assuming that is his problem...) The best testing tool is a DC clampon meter, a tool that I find invaluable when diagnosing starter problems.

I'm sure that a DC Clamp meter is definitely the best option to start with, if its under 10 amps then utilise an in series meter as they are more accurate than most DC clamp meters.

Then again, DC clamp meters are not something that most people have lying around in their garage.