Truck not turning over

Hi I have 1992 C2500 Silverado 350,
I replaced the battery with a brand new one today, now when i turn the key it doesn’t turn over, just click / clunk which seems to be coming from the solenoid. When i turn the ignition on to the start position the battery gauge now climbs to just over 10 or 11 volts, previously it would be around 13 volts on starting.
Im guessing it may be the solenoid but the wiring on the solenoid does not match up to any wiring diagram i’ve seen.
When trying to trace the wiring I found the purple wire (in the second picture) was disconnected and could not see anything it could connect to
Im located in the UK so support for this truck is pretty nonexistent, so any help and advice would be much appreciated.

That sounds like a flat battery.

I would take the connections loose from the solenoid and clean them up anyway. Including the mounting plate, that is the source of the ground.

Keep us updated.

Kevin99 said:

Hi I have 1992 C2500 Silverado 350,
I replaced the battery with a brand new one today, now when i turn the key it doesn’t turn over, just click / clunk which seems to be coming from the solenoid. When i turn the ignition on to the start position the battery gauge now climbs to just over 10 or 11 volts, previously it would be around 13 volts on starting.
Im guessing it may be the solenoid but the wiring on the solenoid does not match up to any wiring diagram i’ve seen.
When trying to trace the wiring I found the purple wire (in the second picture) was disconnected and could not see anything it could connect to
Im located in the UK so support for this truck is pretty nonexistent, so any help and advice would be much appreciated.

Click to expand...

Purple wire goes to the ignition circuit. I agree with @Orpedcrow that you probably have a battery that needs charging. You should be able to get the wiring diagrams from the shop manual downloads available on the forum.

New =/= good for batteries. They can sit on the shelf for a year and still be considered good, and after a year they are supposed to send them back but who knows if that actually happened. A year + old battery will lose a lot of charge. Definitely charge it and if it still doesn't work I would have it load tested.

Orpedcrow said:

That sounds like a flat battery.

Click to expand...

Or maybe poor connection to the cables at the battery… I’ve had that problem before.

Clean up the cable-to-battery connections and retry. They often become oxidized, so look them over.

If you have the “doubled-up” connections on the “+”, they in particular can be problematic; they’re what caused me a similar problem on my Suburban.

If you have a DVM, check the voltage at the battery if the problem persists to help identify if it’s the problem or something else.

1998_K1500_Sub said:

Or maybe poor connection to the cables at the battery… I’ve had that problem before.

Clean up the cable-to-battery connections and retry. They often become oxidized, so look them over.

If you have the “doubled-up” connections on the “+”, they in particular can be problematic; they’re what caused me a similar problem on my Suburban.

If you have a DVM, check the voltage at the battery if the problem persists to help identify if it’s the problem or something else.

Click to expand...

The battery is showing 12.7 volts, and the junction block on the firewall is showing the same voltage.
What i’m thrown by is the solenoid on the fender wall has a maybe 10awg wire (black/red) from the bottom stud going to the firewall junction block, on the same terminal is a similar size Black/red wire which is connected to the battery positive cable, this is pre moulded into the connector. But nothing appears to connect to the starter.

Orpedcrow said:

That sounds like a flat battery.

I would take the connections loose from the solenoid and clean them up anyway. Including the mounting plate, that is the source of the ground.

Keep us updated.

Click to expand...

Battery is showing 12.7 volts, i’ll put it on charge again and see what happens, i’ll also try a remote start switch to rule in or out a switch issue.

1998_K1500_Sub said:

Or maybe poor connection to the cables at the battery… I’ve had that problem before.

Clean up the cable-to-battery connections and retry. They often become oxidized, so look them over.

If you have the “doubled-up” connections on the “+”, they in particular can be problematic; they’re what caused me a similar problem on my Suburban.

If you have a DVM, check the voltage at the battery if the problem persists to help identify if it’s the problem or something else.

Click to expand...

Thanks for that, the cables to the positive post are pre-moulded into the side connector so I assumed it was factory.

Kevin99 said:

The battery is showing 12.7 volts, and the junction block on the firewall is showing the same voltage.

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Both locations will measure the same voltage when there's no load.

The fact it's measuring 12.7 is reassuring, although that doesn't definitively mean the battery's in perfect condition.

Put the battery under load and see what happens to the voltage at both places. Turn on the headlights, interior lights... or even try the starter.

Also, try measuring the voltage from the battery "-" to the engine block when under load (headlights, starter, other loads). It should be very low at all times (a few tenths) except the starter's engaged (then it'll be greater).

Kevin99 said:

1992 C2500 Silverado 350,

Click to expand...

Kevin99 said:

I replaced the battery with a brand new one today, now when i turn the key it doesn’t turn over, just click / clunk which seems to be coming from the solenoid.

Click to expand...

Is it just me? Am I hallucinating? That solenoid on the fender is not part of the GM wiring harness. Somebody added it later.

Looks to me like there's a missing cable on that fender-mounted solenoid, assuming it's for the starter motor and not some other accessory.

How are the wires arranged on the starter solenoid--the one attached directly to the starter motor? I'd expect a heavy cable (~4 gauge) on the big post at 12:00, a heavy cable or copper lug on the big post at 6:00 leading to the starter motor internals, a smaller 12-gauge wire on the "S" terminal, and--maybe--a medium-sized wire of 8, 10, perhaps 12-gauge from the big post at 12:00 up to a junction block somewhere for power distribution.

Kevin99 said:

Im guessing it may be the solenoid but the wiring on the solenoid does not match up to any wiring diagram i’ve seen.

Click to expand...

WHICH solenoid? The one on the fender, or the one attached to the starter motor?