Cruise and Voltage Regulator help!

[J DeMaio]

Hey guys:



Yesterday my cruise control worked and i got onto the interstate today but it didn't work, I fidgeted around with it for a few minutes but it didn't respond a bit to me pushing the buttons, what is wrong?



The next big thing, when I fire up the truck, the voltmeter usually registers very low and doesn't go up to twelve volts for about 5 miles. It always starts, it doesn't act as the battery isn't charging, is it the voltage regulator? A guy I know used to own a 89 Cummins and he said that this was a common problem and a voltage regulator would fix it, was he right?



Hope you can help me with these two delimma's, thanks.



John

 

[Hutchew]

Might be.........

the PCM or ECM, whatever it's called, behind the battery under the driver fender. Check your connections. I'm not sure about the 89 model, but the later CTD trucks voltage was regulated through the PCM or ECM, whatever it's called, along with the cruise control. I do know that mine will run a little shy of voltage until it warms up and the grid heaters kick off, or so it seems... ... .....

 

[J DeMaio]

How much does one of those cost? Is the only available place to get it the stealer? Do you have to re-program anything when installing a new one?



Yea, I know that the voltage regulates until it warms up, but this one always fluctuates below 12 volts and stays there for quite some time, no matter how long it idles or how much you rev it up.

 

[Hutchew]

Hmmmmmmmm........

It depends on your truck, but when I priced a new one for mine, it was @ $450. 00 if I recall correctly. Others were more expensive and some were less. You don't have to reprogram anything, just unhook the battery, unplug the old one, stick in the new.

Before I did that, though, I would double-check all the connections on your alternator, engine, ECM, etc. If that doesn't fix the problem, NAPA can check your alternator and possibly the ECM for you.

 

[J DeMaio]

Okay guys. Update. I called AutoZone and they have only one type for my truck for $160, that was the only one they could get and I have to find the number on my old one. So... where exactly is this ECM located? The guy at AutoZone said it would be behind the glove box under the dash and this all had to come apart, is he right?



Thanks,



John

 

[AlK]

The engine controller is located in the engine compartment, behind the battery and under the left front fender.

---

Al

 

[dodgenstein]

If the voltage regulator is bad, there is an aftermarket setup to add an older style external regulator like the ones used in the late 70's Chrysler products. When my regulator went out in my 91 Ramcharger,I believe the kit was about $30+the new regulator,much cheaper than a new ECM.

 

[J DeMaio]

The only thing that I could see was bolted to the inner fender, it was a bracked and it had two big pieces on it with two terminals on each piece. Then there were some more wires bolted to the bracket, is this it or is this for the intake heater grid?



Dodgezilla: Where did you purchase that kit at?



Thanks guys,

John

 

[Hutchew]

The thing behind the glovebox.....

Is the controller for the rear wheel ABS. I had only one large plastic box behind the battery, about 3" thick, 6-7" tall, 9-10" wide. There was only one harness connection on it. Can't tell you what you are looking at, being two boxes and two connectors. Maybe they changed things in 93? The heater grid is controlled by this box, you will have a couple of wires from the air temp sensor, and a couple of wires to the heater relays mounted on the fenderwell, along with about 20-30 more, all inside the harness.

You can use a early model voltage regulator, I think they used these right up untill 89-90.

 

[Braveair78]

Low Voltage Problems

It sounds as if your low voltage problem is the cold weather and the cycling of the heater grid on the intake. The 5 miles that you describe is the time it takes for the engine to warm up. The computer thru sensors determines how long to cycle the grid. If it takes forever for the "wait to start" light to go out then chances are it is pretty nippy outside and the grid will cycle... you can hear the clicks of the relays which accompany the rises drops in voltage (headlights as well if they are on) when really cold the grid will cycle while the engine is on... till warm. While cycling the voltage should be between 9-12 volts and when the grid is finally switched off it will be between 12-14.

 

[Braveair78]

Meant 8-12 volts on the swing..... also the ECM is on the drivers side front fender behind the battery