Oil Pressure, Radiator, and Battery/Charge Light all come on at the same time.

[Headhunter38]

Like the title says, all three of those lights come on at the same. It happens when revving the motor high and disappears immediately once the rpms drop again. Im not sure exactly which rpm though since my van does not have a tachometer. It happens both in nuetral and in gear, though i havent tested each gear as im not really keen to go out and rev it up to 5 or 6k in 5th. I have a mechanical oil pressure guage and pressure is fine when this happens so im betting that the other two lights coming on are not because they are actually low like the lights would indicate. does anyone have any suggestions on what could cause this, or have had the same issue? btw its an 87 4wd manual, not sure if that matters with an engine issue like this.

[JDM VANMAN]

Amazing I just started to have the same issue!!!


Here’s a photo of the dash lights on start up-





Here’s a video I took showing as I accelerate the lights start to flicker-


https://www.youtube.com/watch?v=eUME-ZgtnXQ


Since the Brake Light is on I checked the brake fluid and its fine, the Charge Light is on and charging system is good Battery, Starter, and Alternator are performing at optimum level, Radiator Light and the fluid is good…. The guy at O’reilly’s said its probably a loose wire behind the instrument cluster that starts to vibrate when then van is accelerating???


What do you think, similar issue?

JDM

[originalkwyjibo]

Sounds like classic Christmas dash fellas. Possibly a regulator issue causing an overcharge condition at higher RPMs.

[Headhunter38]

Thats exactly what mine is doing too. Though it sound like yours is doing at a lower rpm than based on the video. Mine does it around 35mph -40mph in 2nd gear, whatever rpm that happens to be i guess. I actually didnt notice it until i was driving at night since its very faint during the day and going up to 35mph in 2nd gear isnt a common thing i do. The battery the van came with did just quit on my recently so ifs an overcharge issue that would make sense. Ill check the voltage regulator like originalkwyjibo suggests it is once i finish up theexhaust manifold stud repair and have the van driving again.

[llamavan]

Sounds like classic Christmas dash fellas. Possibly a regulator issue causing an overcharge condition at higher RPMs.

Gwen

[JDM VANMAN]

Nice thank you for confirming and pointing us in the right direction, I put in a order for 3 regulators that should be here in the next week or so.

JDM

[MarkH]

To check that the regulator is working, I'd put a volt meter on the battery when the engine is off and check that the voltage is around 12 and a half volts or so. Then I'd start the engine and see that the voltage goes up to 13.8 or so volts. Then rev the engine and see that the voltage stays about the same. This dash light issue happened to me and it turned out to be a intermittently-broken wire in the alternator wiring harness. When I wiggled the wiring harness with the engine running the lights would go on and off.

[originalkwyjibo]

I had a diode burn out in the warning light circuit in the instrument cluster that caused my light to come on several years ago. There's no substitute for thorough troubleshooting. Otherwise you are relying on luck to find the problem before the bank account is empty.

[JDM VANMAN]

Finally got around to addressing this issue, I got most of the parts I was thinking I would need but of course theres gonna be something that I’ll forget, unaware of or just didn’t even think of it.


Heres some parts that I ordered to rebuild the existing alternator and ordered 2 more alternators just in case I get a bad one.














Before pulling the old alternator we did a test on it to try and find the voltage ripple to narrow down the issue. The voltage was fluctuating 11.8 to 14.9, knowing that the alternator was pulled out.





The new ACDelco Gold went in and the voltage test was done again to confirm this is a good unit but then we were getting 12.6 to 12.8 and it wouldn’t go any higher, so out came the ACDelco and unfortunately I didn’t bring the other new unit so then the original unit pulled was gonna be torn apart for inspection and repair.


The unit was taken apart and the diodes looked good, brushes looked good and almost new, the voltage regulator looked like it was the culprit so it was replace with the new part and put back together for install. After rebuilding and installing the unit we did the voltage test again and now we’re getting the same thing as before 11.8 to 12.9 volts.


So now we dig deeper into this and find that the wiring harness is compromised at the connector that plugs into the alternator…. Being the its Labor Day and theres no time to run around to the parts store we pulled out the box for spare wires and connectors to repair the harness.











Replaced the wire connectors and ran new wire and installed it into the plug connector. Sorry some of the last photos were blurry and I didn’t get more photos due to time constraints of pulling the alternator 3 times and then repairing the wiring harness.


Got the rebuilt alternator installed, wiring harness plugged in and fired it up and then got this reading-





We let the van run for about 10 -15 minutes to let the voltage regulator “burn-in” or ‘break in’ and then the voltage started to level back out to 14.1-14.5 range and the dash warning lights were all gone. Drove the van 100 miles to test and no more lights!!


Thank you for the help!!!


JDM

[Headhunter38]

Glad you got yours fixed! This is good to know what to look at when I can get to addressing the issue for my van. Still trying to get it pass CA smog tests first though.

[JDM VANMAN]

Thank you just for clarification the rebuilt alternator was a used one pulled a few years ago, my plan was to put in one of the last Denso rebuilt alternator but I chose the used part and put the Denso back on the shelf along with the ACDelco's as a memento I guess.

As for your CA Smog issue have you looked at this thread-

https://www.toyotavantech.com/forum/...=pass+emission

JDM

[Toyota2RZ-E]

Sounds like classic Christmas dash fellas. Possibly a regulator issue causing an overcharge condition at higher RPMs.

I had the xmas light thing happen to me if I wiggled the wiring at the back of the alternator they came and went. Turned out to be worn out brushes in the alternator. The brushes cost me about $5 and can be change without removing the alternator on my 1998 commuter 2.4.