59FORD

Doc

If you can't find a problem OR if it's in the PCM and you don't want to
drop a wad you can use one of these and make a "onewire" that's
what I had to do to get rid of the pulsing voltage.







NOTE: Please ignore the photo quality I am under cheap lights in the computer room.


I can even load a pic of the install but that will have to be tomorrow.

I got a deal on mine so I bought 2 ..... just in case.

Easy to install and now my voltage sits at 14.2 like it should.


59

got...DIESEL?

as of yet no one has suggested checking voltage at the batterey AND the alternator. No more than 1/2 vdc drop between the two readings....running or not, but especially running when there is a load on the circuit..(supposed charging current). If more, check every connection between the two.

Next place a volt meter across the two field wires while still hooked up to the alternator. If the PCM is funtioning accurately, it should be supplying full system voltage trying to get the alternator to bring system voltage up. If you see full voltage on these two field studs, and see matching battery voltage on the output stud of the alternator, you have a bad component or two in your alternator. You don't know how often I see someone remove a non-working alternator, bringing to me only to have it work wonderfully on the test bench. This is usually from short brushes....they get knocked around pulling the alt, riding in the floorboard and making it to the bench, but usually will fail again when re-installed. Brushes should not be more than $2.00, and THAT'S even a rip off. I pay 10 cents a piece for them in 25 shot bags. Any reputable rebuilder will have them...if not call Romaine Electric in Seattle....largest rebuilder supplier in the country.

Back on task....if you DON't have field voltage at the field studs, guess what? Yep, full field it.....just like everyone has said, pull the field wires and ground one stud and power up the second with pos. With no loads on, this should make the voltage go to 16 and beyond. Obviously don't leave it this way long....Turn every load on the truck on at idle. This will simulate a load bench. Voltage should stay high, if not hold rpm's at 1200, it will usually come to life full output with a few rpms if it doesn't have any problems. Next check the field wires to the PCM then get ready to convert it or buy it.....there are plenty of resources here to convert it, I won't throw another one out there.

I believe yours also has the battery temp sensor, am I right? I believe I have heard problems with these causing the same issue. Most bypass them.....worth doing a search on to get the skinny on the sensor probs.

GL....keep us posted.

Haulin_in_Dixie

After reading some of the posts, try this. On the left side is the temperature sensor, under the battery. Wonder if it might be corroded. Find the wire and it is maybe six inches long and has a plug. Just unplug it. That will make a small reduction in the charge rate in the winter, not much difference in the summer. It it is the culpret, that will eliminate it from the equasion.

Dr. Evil

Well, still no real progress.

Previous owner wired a few things in...

I have both batterys disconnected - checked continuity between + and - battery cables. Meter shows a short - Im pretty sure it shouldnt be shorted. Im pulling my hair out now.

It sure gets dark early these days. Pesky job is keeping me from what is really important

Jeff in TD

How many ohms between pos and neg with batteries disconnected? (Make sure everything is off or unplugged, including the underhood light)...

Geico266

With the batteries connected take out each fuse and tap it on the fuse socket. You'll see a tiny spark on the circuit that is drawing power. Check your cig lighters. Make sure there are no coins in them. Dome lights going off? Back up lights off? Start with the simple stuff.

Good luck Doc, wish I was closer I would assist.

Dr. Evil

You guys are awesome - thanks for sticking with me and apologies for jumping from batteries, to alternator to a short. Ill take mechanical over electrical any day.

RAM2940

59Ford,
I sent you a pm a couple weeks ago about the pulsating light problem. Could you possibly send me the information and picture of the install to a one wire system. I sure would like to get the electric on this 1990 d250 from pulsating.

torquefan

Hey Dr.- Is your truck a quad cab? If it is, you may be on a wild goose chase looking for a draw. When you shut off the key on a quad cab, the electric seat belt locks are designed to stay powered up for 20 or 40 minutes. They draw close to an amp, if I remember. I went through that back when I worked for Dodge. I think it's in the service manual somewhere. Anyway, if you're seeing a big draw with the key off, that's probably all it is.

Dr. Evil

NO WAY - yes it is a QUAD and the draw is somewhere around 500 mA to an amp (depends if the door is open or not) !!! I am going to keep poking around a bit more since there is a bunch of aftermarket stuff that I havent looked at yet.

BUT, I do think I owe you a BEER...are u right in Calgary ??

torquefan

Yep, living in Calgary, working in Cochrane. We'll have to get together sometime. I'll try to look up the specifics on that seatbelt draw issue and get back to you.

Dr. Evil

Sure - that sounds good. Cochrane eh??? Nice local...

I STILL think I may have a short somewhere. I took a break from it tonight...had both CTD's down.

Dr. Evil

Who wants to buy a 98 12V quad??

Just kidding....but I AM getting a bit frustrated.

Just as a refresher, ths truck is pretty new to me. Batteries died about a weekd after I brought the truck home. I initially though that it was the batteries -- so I replaced them. Truck ran good for a while. Then the batteries died again - these are big 1000 cca batteries. Had the batteries load tested - they are good. Had the alternator tested (3 seperate tests).

After a bit of searching at some of the accessories put on the truck by the previous owner I think I finally found the cause of the short I am experiencing.

I was measuring 0.78 ohms across the drivers side battery cables (with batteries disconnected).....I assume this should be open...correct?? When I pull fuse #12 (I.O.D.) the short disappears. My owners manual says this fuse is "AIRBAG DIAGNOSTIC MODULE, CLUSTER, MESSAGE CENTER"

I assume leaving this pulled will disable the airbags??? I havent installed the batteries yet so dont know if the cluster works or not....

HELP??? ANY suggestions.

Thanks for reading my plight guys...any more suggestions would be greatly appreciated.

torquefan

Sorry Dr., didn't get a chance to look further into the manual for that draw thing. It's quite possible those seatbelt locks run off that circuit. What you should do is hook up an ammeter in series with your battery (unhook your other battery). You will probably see a draw of 500-1000 milliamps. Leave the ammeter in place for up to an hour, and see if anything times out. I'll bet you have under 35 milliamps after that hour.

Dr. Evil

Even so, I still dont see how that can kill the batteries??