Warning Light Issues (1 Viewer)

[LCBC]

My brake and filter warning lights came on the other day (85 BJ 60, 3B). They came on at low idle, then seemed to dissapear after RPM was up for a while. My thought was it was the alternator. I tried to eliminate other possible causes first; drained the sedimentor, checked vaccum, checked battery connections etc... Put a volt meter on the alt and it was a little low so i took it in to get rebulit. Put it back in and drove around for a while; the warning lights are still on but they now blink when RPM is up? Re torqued the bolts and checked connections, belt tension etc... and nothing, still the same results. Does anyone have any idea what could be causing this? Have I missed something that could be causing the waring lights to come on?

 

[Dieseler]

Usually it's the alt brushes but since your alt was done thats eliminated.
Run a search you will get the other options to look at.

 

[onefsatchevy]

Did you do the rebuild or pay to have it done? I have seen a couple of paid for "rebuild" jobs that were very poorly done. It may need more than just brushes, the armature may also need replacing. And they may not have replaced the regulator, which may result in you getting AC current out of it which can cause all sorts of problems. Easy test is to put a simple volt meter across it, you will always get a very little bit of AC, but much more than a few milivolts and there is your problem.

 

[LCBC]

I took it to a shop and had it rebuilt. Just put a volmeter on the batteries with the engine stopped and got 12.4 v per side. Fired it up and let it run for a while then checked them with the engine running, got 12.5 per side? Checked on the alt lead and got 12.5 as well. Shouldn't it be kicking out around 14 v?

 

[lostmarbles]

I took it to a shop and had it rebuilt. Just put a volmeter on the batteries with the engine stopped and got 12.4 v per side. Fired it up and let it run for a while then checked them with the engine running, got 12.5 per side? Checked on the alt lead and got 12.5 as well. Shouldn't it be kicking out around 14 v?

Yeah. Depending on the state of your battery (and on what electrical loads you have in operation - if any) I'd expect readings from 13.5V to 14.7V.

If it's externally regulated, perhaps your regulator is faulty?

 

[ForealBoreal]

what about a ground strap?

The other thing that I would look at is to make sure the connection plug is clean and put some dielectric grease i there.
I suspect a faulty regulator or a bad plug.

 

[blis]

Sounds like regulator or alt brushes to me since it gives so low voltage... Also that low voltage is most likely your reason for the lights coming up...

 

[LCBC]

I'll check those things out. What is strange is the battery warning light isn't on. The brake and filter lights are on steady below 2000 rpm, then blink above 2000 RPM?

 

[lostmarbles]

I'll check those things out. What is strange is the battery warning light isn't on. The brake and filter lights are on steady below 2000 rpm, then blink above 2000 RPM?

Is your alternator internally regulated or externally regulated?

And did the shop who rebuilt your alternator do a performance check on it after they rebuilt it?

 

[LCBC]

Not sure, how do i check? I believe the regulator is internal... I called the shop this morning, they told me to bring it in and they will bench test it.

The bizarreness conitunes though... on my drive home my oil pressure guage goes dead, showing no oil pressure? Temperature doesnt move though, so i hope i still have oil pressure? Should i be worried about oil pressure? I cant figure out what the heck is going on here?

 

[lostmarbles]

Not sure, how do i check? I believe the regulator is internal... I called the shop this morning, they told me to bring it in and they will bench test it.

The bizarreness conitunes though... on my drive home my oil pressure guage goes dead, showing no oil pressure? Temperature doesnt move though, so i hope i still have oil pressure? Should i be worried about oil pressure? I cant figure out what the heck is going on here?

I'd concentrate on one issue at a time LCBC.

If you're only getting 12.5V across a battery with your engine running that proves a charging problem. So I reckon you should fix this first.

Hopefully the oil pressure gauge malfunction is related ... but obviously it would pay to check your oil level, check for oil leaks, and listen for unusual sounds if you are running your cruiser now with it showing nothing on the oil gauge.



PS. You could also lift the oil filler cap on the valve cover and confirm that there's the usual amount of oil getting up there.

 

[LCBC]

Yeah, no oild leaks or change in oil level, just looks like a gauge malfunction. Going to yank the alt, and get it checked out again; hopefully its the cause of all the problems.

 

[Dieseler]

Is there a low battery warning light I dont believe I have ever seen it if one does exist and I have had batteries go flat and alts crapout but no battery light go on.
I guess it is like that Amp gauge that never moves left or right of center.

 

[Tin basher]

My 60 does the same thing with the fuel filter and brake warning lites
Intermitent and going from hi to low beam would turn them out
It was bad grounds under the dash cleaned them up
And no more warning lites

 

[LCBC]

Tin basher, whereabouts are the grounds under the dash?

 

[LCBC]

So I got the Alt back from the shop, they went through it again and replaced the regulator this time. Put it back in the truck, fired it up, warning lights still on. Drove around the block, lights still on; adjusted the belt, warning lights off and stayed off. So it looks like it was a faulty regulator.

Now I have to deal with the oil pressure guage, it was completely dead (on low - 0) but after driving around it has gone to high and wont move, what could be causing this (loose wire)? I have been looking at the FSM and cant find where the sending unit is; can anyone help out with this one?

Thanks!

 

[blis]

Cant remember the exact spot but there should be 2 sender units on the block (passenger side I believe), the smaller one of those 2 should be the unit that sends information to your gauge...

 

[Eric Winkworth]

I have what sounds to be the same issue...

I also had my alternator rebuilt by a local shop...

Ever since getting my truck when started it always has had to be revved above 2000 rpm to get the warning lights off and start charging properly via the ammeter gauge... Once I do this it's always been fine even on 10+ hour drives, idling etc...

This winter I had an issue with the lights coming on at speed over bumps, I reworked the main ground under the hood and it seemed to fix it for a while... Then I noticed at the lowest it can idle I can still get them to come on and it also shows on the factory ammeter as not charging when the idiot lights come on... Once I rev it above 2000rpm again, they go off it starts showing on the gauge as charging... Also when the idiot lights are going on and/or off I can hear a relay click I think near the glove box somewhere...

Should I assume regulator or a ground issue under the dash? I am pretty sure a 1986 CDM spec is internally regulated any idea on where to source a regulator?

Thanks for any help!

 

[David*BJ70]

Cancel the old oil pressur sensor and put a mech sensor w/gauge. It is the one look like a «bell».

While your there, buy a 3 mechanical gauges unit with a volmeter and T° sensor.... I do not thrust my 25+ old gauge and sensor

 

[David*BJ70]

Cant remember the exact spot but there should be 2 sender units on the block (passenger side I believe), the smaller one of those 2 should be the unit that sends information to your gauge...

The smaller one send information to the EDIC.