Hyundai r130 rpm sensor

Load test came back fine, lamp stayed lit with no dimming.

Your lamp setup would probably be like what the display draws in terms of power. If you've tested the wiring properly, there shouldn't be any wiring issues.

I haven't tested a 9007 bulb by itself to check its draw, but if it only pulls 1.6 amps like you mentioned, the wiring should be fine. If it draws less than that and a suspect wire pulls a little more when you test it, that points to a wire grounding problem.

Engine vibration could play a role too, but reading through your post again, I'd lean toward the aftermarket sensor being the problem. What does an OEM sensor cost? I wouldn't go with an aftermarket one after watching all those videos about them failing.

The sensor's outputting 0.5A while the engine runs. I don't think the sensor itself is the problem. I've got other stuff not working either—temp gauge and low water alarm both out.

Do you have clean power going to the monitor and a clean ground back to the battery? I'm running out of ideas since two other things in the same monitor are acting up too. It seems unlikely they'd all fail at once unless something feeds power to all of them or the return ground is failing under load. Could you try running a live battery wire directly to the monitor and another one back to the battery to rule that out?

I checked CN-8 (3) on both the harness and computer sides and it's not the issue.

When certain dashboard readings drop out like the coolant temperature sensor or flywheel speed sensor while other stuff keeps working fine, it's often a pins or wiring issue at the CN-7 harness connection. That's what ChatGPT suggested anyway.

So is CN57(3) to chassis ground supposed to be okay or not? I was just checking the monitor to sensor schematic. Something's clearly off. Did the old sensor give you the same readings as the aftermarket one?

So CN57 (3) to chassis was open—does that mean the cluster is bad?

A cluster replacement isn't cheap, and there's always the worry it won't be available down the line. I'm not sure what an OEM temperature sender runs, but it looks like the cluster might be the issue. Have you been able to get any quotes yet on either of those parts?

ChatGPT reckons your cluster works fine (passes the bulb test) and your computer works fine (runs the excavator perfectly), so don't spend money on expensive parts. The problem is probably a broken or corroded communication wire between the two units. Even if everything runs okay, the computer won't send RPM and temperature data to the dash if it thinks the engine isn't turning over. It checks this through the alternator's R-Terminal. So if the machine charges fine but that signal wire is cut or broken near the engine block, the computer goes silent on the dashboard network. Worth checking tomorrow. A new cluster costs around $1200.

Could be you've got too much AC voltage running to the cluster and ECM—worth checking since it only takes a couple minutes and you can rule it out. Hard to say what's accurate on those websites anyway. Once you've tested everything, you'll just have to give it a shot and hope it works right away.

So I figured out what was wrong—I'd hooked it up to terminal I instead of R for the signal power. Terminal I is 24v while R is 13v, at least that's what I found out. Switched it over to the correct terminal but it still isn't working.

The R-Terminal is at the center of the stator and typically sits at exactly half the output voltage. From what I've seen, most of these output AC volts before the diodes convert it to DC. If a wire ends up on the wrong terminal, it can be tough to track down unless you're testing pin by pin and happen to catch a mixed-up number.

Looks like ChatGPT was off on that one. The manual says it should be getting 24v.

Looking at the schematic, I'm seeing 25.2 volts from the battery positive when the batteries are charged, probably hitting 28 volts once the engine's running. Pin 4 going to the CPU Controller looks like it's the control signal, which makes sense since it's showing 20-25 volts telling the alternator to ramp up voltage and charge amps.

Test point 5 is showing 25v, but points 6 and 7 are only at 5v. I'm not sure what that means, but I think that might be where the problem starts. I need 24v at that point.

Check connector 53 Pin #8 and make sure it matches Pin #7, which is marked 6 on the diagram. Something's off unless the CPU Controller is cutting the voltage or not outputting enough power.

Yeah, CN53 Pin 7 and 8 both showed 5v. Since CN53 only has those 2 wires, I'm wondering if I could just jump 24v to that connector and see if it works.

I'm wondering if the CPU isn't outputting enough voltage. It might be safer to run the voltage through a bulb instead if there's a way to do that. I don't want to risk blowing the CPU with high voltage, even though it could be faulty itself or the wiring loop from 6-7 might be too weak or faulty. Could you test this with a bulb? I'd hate to send you down a rabbit hole that ends up blowing the computer or damaging it.

I'm supposed to have 24v at pin 7, but I'm not sure if that's coming from the cpu or going into it. If it's going into the cpu, could I jumper off the battery or another 24v source and plug that into the cpu instead?