Ballist Resistor?

JNG 92XJ · May 11, 2005

I have a 1992 Cerokee Limited 4.0 L, auto everthing, select track transfer case, 217,000 miles.

Yesterday, when trying to go home from work, the Jeep would start ... run for about 3 seconds ... then die. I repeated this about 40 times.

I had it towed to the local Stealership, and they tell me that the "Ballist Resistor" has failed. The repair cost, (diagnostic time = 1.5hr, plus labor of 1/2 hour, plus the cost of the part = $9) will cost me $148.98.

All of the local parts stores say there is no such part listed for my Jeep.

I have a ceramic block on my drivers side fender, held on wih one bolt, with 2 wires connected to it. Is this the "ballist resistor"?

BrettM · May 11, 2005

yep that's it, had the EXACT same thing happen to me, except I didn't take it to the dealer, I got on the forum here and the knowledgeable people saved me $100.

JNG 92XJ · May 11, 2005

Thanks for the reply.

I thought that Chrysler got ride of the "Ballist Resistor".

I had a dodge Dart back in the early 80's and I had to carry a spare ballist resistor in the glove box because they went out every 2 months or so.

Isn't "modern" technology great.

BrettM · May 11, 2005

my 88 has one, and I've heard they are gone from later years, but if you have one next to the airbox then I guess it was after 92 that they got rid of it.

Hickey · May 11, 2005

BrettM said:
my 88 has one, and I've heard they are gone from later years, but if you have one next to the airbox then I guess it was after 92 that they got rid of it.

I have one on my 92 also. It was booty-fab bypassed when I bought the Jeep. I recently cleaned up the connection, leaving it bypassed.

Yucca-Man · May 11, 2005

Just for search purposes, it's a "ballast resistor" (note the spelling) and I think it disappeared after 92 or 93, thankfully. At least we kept our trusty CPSs!!

Eagle · May 11, 2005

The ballast resistor on the old Mopars was for the coil, to reduce running voltage to the ignition. (God only knows WHY they wanted to reduce voltage to the ignition, but they did.) The ballast resistor in the XJ is to reduce voltage to the fuel pump.

5-90 · May 11, 2005

The ignition ballast resistor was to reduce current in the coil, supposedly to help prevent overdriving the coil. It was bypassed during start to get a "hotter" spark to kick things over.

The XJ ballast resistor started as a voluntary recall in the 1988MY to reduce fuel pump noise transmitted through the frame - the ballast resistor reduced the current to the pump slightly to cut down the noise. It is not electrically necessary for our purposes, and can actually be deleted with minimal impact.

The "ballast resistor" will probably never quite go away - but it might. Meanwhile, w've still got them, but you can delete it if you want with no ill effects. The setup with the fuel pump is probably like the old ignition setups - but I'd have to look to be sure.

5-90

wrong1 · May 11, 2005

As said, thats the part. Mine was a 1.1 Ohm I when I replaced it awhile back on my 89. It had to be the factory original cause it was nothing but white powder with a coil of wire running through it.

GSequoia · May 11, 2005

I just deleted mine last week, was having some connection issues so I tossed it. No problems to report, I do notice a louder fuel pump sound but once I get about 30mph the tires drown that sound out

flexjay87 · May 12, 2005

i had the same thing happen, pulled my hair out tryin to figure it out. anyhow $148.00 sounds awful high for a 30 second part change?

BrettM · May 12, 2005

scott w said:
i had the same thing happen, pulled my hair out tryin to figure it out. anyhow $148.00 sounds awful high for a 30 second part change?

"diagnostic time"

in other words, we're dumb and can't figure it out, so bend over and pay up.

JNG 92XJ · May 12, 2005

Thanks for all the input. The repair total was $146.00, so I saved 2 bucks.

Sorry about the spelling of "ballast". It was a long day and the tavern is just next door. It was 4 glasses later that I thought to check this list.

The bypass sounds like the fix if it happens again.

Matthew Currie · May 12, 2005

Eagle said:
The ballast resistor on the old Mopars was for the coil, to reduce running voltage to the ignition. (God only knows WHY they wanted to reduce voltage to the ignition, but they did.) The ballast resistor in the XJ is to reduce voltage to the fuel pump.

The simple answer is that, rather than simply producing a 12 volt coil, as was common in European cars, the American manufacturers used what was essentially a 6 volt coil, giving it overvoltage when starting which would cook it unless ballasted for running. A common mistake of shade tree mechanics back in the old days was to take a "12 volt" coil from a Chevy or something and put it in a VW or a Saab, and die an hour later from a fried coil. Now that we have electronic ignitions that can shoot a spark across the room, it's not the issue it was back in the days of points'n'condensers. A slightly out-of-tune VW could be essentially out of action on one of those "dew-forms-on-everything" days we get so often in New England, unless you lived at the top of a good steep hill, where an American clunker with a ballasted coil would fire under water. This is one thing the Americans definitely got right!

BIGSLVRXJ · May 12, 2005

Hate to be a thread hijacker but I wonder if my 90 has a bad ballast resistor. When I get going about 55-65 on warm days I hear a whiiiir and it vibrates the frame. I know it is the fuel pump going out or the ballast resistor. Which would you guys bet on?

JoBo · May 12, 2005

JNG 92XJ said:
Thanks for the reply.

I thought that Chrysler got ride of the "Ballist Resistor".

I had a dodge Dart back in the early 80's and I had to carry a spare ballist resistor in the glove box because they went out every 2 months or so.

Isn't "modern" technology great.

Your dart had it on the coil! When talking XJ's it's on the fuel pump. Same reason just fuel instead of spark.

JoBo

Eagle · May 12, 2005

CollinM said:
Hate to be a thread hijacker but I wonder if my 90 has a bad ballast resistor. When I get going about 55-65 on warm days I hear a whiiiir and it vibrates the frame. I know it is the fuel pump going out or the ballast resistor. Which would you guys bet on?

Yes, the 90 has the ballast resister. Look on the inside of the driver's side fender, just behind the air box. It's a white-ish ceramic block a couple of inches long with about a 12-gauge wire going to each end. It doesn't have any moving parts and it doesn't make any noise.

BIGSLVRXJ · May 13, 2005

Yeah I know where it is I'm just not sure how to test it.

red91 · May 13, 2005

CollinM said:
Hate to be a thread hijacker but I wonder if my 90 has a bad ballast resistor. When I get going about 55-65 on warm days I hear a whiiiir and it vibrates the frame. I know it is the fuel pump going out or the ballast resistor. Which would you guys bet on?

Collin...I bet its the Gerbil in the back seat by the jack. NOT your pump or resistor.

wrong1 · May 13, 2005

To test it is easy.

Just unplug the 2 wires from it and hook an Ohm meter up to the 2 terminals of the resistor. If it should be less than 2 Ohms (like 1-1.5 Ohms) if its good.

Ballist Resistor?

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Member # 683

Lifetime NAXJA Member

NAXJA Forum User

NAXJA Forum User

Everyone says I'm a jerk.

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

NAXJA Member #760

NAXJA Forum User

NAXJA Forum User

Lifetime NAXJA Member

NAXJA Forum User

NAXJA Forum User

NAXJA Forum User

Similar threads