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Randall C
Randall C, ASE Master Technician
Category: Dodge
Satisfied Customers: 12880
Experience:  ASE Master Tech, 32 years Diag/Electrical Specialist
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Dodge Caravan SE my headlights keep flickering on n off while

Customer Question

my headlights keep flickering on n off while driving and I lose all instrument lights, gas,temp needles go up n down and door locks go on n off...what could this be..the engine never cuts off...
Submitted: 6 years ago.
Category: Dodge
Expert:  Randall C replied 6 years ago.
hello, what year is the van? do you have a voltmeter to test something?
Customer: replied 6 years ago.
my van is a 1998...yes I have my husbands voltmeter I have the fluke T2 electrical tester
Expert:  Randall C replied 6 years ago.
Thanks. I would really like to have van at full temp and hook meter to battery and with running, watch the charge voltage for say 5-10 minutes while at idle and maybe evne whiel reving up engine some. I need to know if the charge volts stay steady at around 13.8-14.2 volts at all times.
Customer: replied 6 years ago.
ok I'm going out now..will get back to you in 10 -15 minutes...i know when autozone store tested it last night after we drove 10 miles there and it was off it was full charged he said..but I will do this and get back with you in a few minutes...
Expert:  Randall C replied 6 years ago.
Not full charged but I am looking for possible erratic readings from alternator thus why you need to check at idle, reving, with lights on, wipers on, heater on etc to put a load on alternator. I need to know if charging is holding steady at 13.8-14.2 under above conditions
Customer: replied 6 years ago.
I had heat on, radio on, reved engine and the meter stayed constant..and no flickering incident during this..
Expert:  Randall C replied 6 years ago.
when can the flickering be duplicated. Is it often or rare?
Customer: replied 6 years ago.
It just started two days ago, I was driving for about 3 minutes and heard the door locks going up n down ..then yesterday I was driving my daughter to school..all the way there it was ok and half way back home everything started going was about 4-5 miles driving at that point where as the day before was only 1 mile barely , then last night going to parts store, it started about half mile from home the headlight went out door locks started and dash lights went out,and they kept coming on n off all the way to store about 8 miles away..but it was ok this morning driving to my sons school n back..but engine was cold it's only in 30's outside..but we did idle test yesterday without meter and the flickering happened and it sat all day with one battery cable off...
Expert:  Randall C replied 6 years ago.
This could be tricky to find. If I have to take a stab at it, I am leaning more to the BCm or body control module. it is a computer that controls near everything you mention. the problem is unless the module if 100% fialing, usuallly, only a few circuits are affected. This is why it is very importnat to have ameter on the battery when problem is happening. It could be the PCM :powertrain module as it controls the charging. With it being intermittant, the battery will stay charged . If you can catch the flickering with meter on battery and the volts drop/rise , then i am leaning to the PCm or interaml alternator problem. If you can not duplictec, this makes it tough. If the flicckering happens and charge volts stay ok the entire time, then i am lening to the BCM as the problem.

he body control module (BCM) supplies vehicle occupants with visual and audible information and controls various vehicle functions, To provide and receive information, the module is interfaced to the vehicle's serial bus communications network (the Chrysler Collision Detection bus [or CCD bus]). This network consists of the powertrain control module (PCM) , the transmission control module (TCM) , the electro/mechanical instrument cluster (MIC) , the airbag control module (ACM) , the compass/mini-trip module and the controller antilock brake (CAB) module. The BCM is operational when battery power is supplied to the module. Ignition switch power is needed for ignition switch functions.

The body control module provides the following features:

  • automatic door locks
  • battery protection
  • chimes
  • compass/mini-trip support
  • courtesy lamps
  • BCM diagnostic support
  • door lock inhibit
  • headlamp time delay
  • ignition key lamp
  • illuminated entry
  • instrument panel dimming
  • mechanical instrument cluster support
  • power door locks (with/without remote keyless entry)
  • sliding door memory lock
  • vehicle theft security system (VTSS)
  • windshield wipers / washers (front and rear)

Customer: replied 6 years ago.
Are the flashers controlled by this bcm also? because when I'm driving and It happens I put the flashers on and they stay on and don't flicker or anything when the others do? also when we were playing with the relays under the hood there was this clicking something shorting out when everything started flickering...
Expert:  Randall C replied 6 years ago.
This is new info. Flashers not controlled y BCM. Now.. you said playing with relays. Did you move something and then the problem happened OR did you just hear relays when problem was happening
Customer: replied 6 years ago.
just heard them when the problem was happening...when my husband would check them to make sure none were loose , we heard the clicking was like when u jump start a vehicle and you hear that sparking noise..thats what it sounded like...he pulled a couple out and put them back in but the problem was happening before anything was touched...
Expert:  Randall C replied 6 years ago.
ok, at this stage we are back to the charging system and hope? the problem will surface with meter on battery. I really need to know if charging holds steady when problem happens. I do not wnat you to repalce BCM if i feel we may go another route. i realize diffult when not happening all the time but maybe? it can be caught with meter on battery when flickering happens? this would then lead to charging problem. If meter stays steady, then I go wih more BCm failing
Customer: replied 6 years ago.
another question, when all the flickering was happening last night my husband was following me, when the headlights went out, he said the rear parking lights never went out , and as I stated earlier, yesterday we pulled the battery cables off with the vehicle still running and it never shut off, it kept running with battery cable removed...could the alternator be going bad?(my husband is on phone asking me to ask you this)..that the alternator is kicking in n out making this stuff happen...
Expert:  Randall C replied 6 years ago.
What you need to understand is Dodge does not use just an alternator for charging. Actually,, the PCM ( computer) controls all charging. It is more common for the PCM to go bad rather than alternator on a Dodge. It is different design than most vehicles. We are back to the test with meter at battery. We need the problem to happen with meter on to see if meter drops. I HIGHLY do NOT recommend leaving the battery cable off on this design with computer control. You can very easily damage the computer. That type of test was done with vehicles along time ago with different non computer controlled charging system > it means nothing nowadays
Customer: replied 6 years ago.
Ok Tracer, we just spent 45 minutes with meter at battery and had all sorts of glitches, the battery was 10+ at startup, idle was 14, with heat lights wipers etc stayed at 14/13 rear defroster dropped it to 12, sometimes with all on it just keep going from 14/13...this went on with 14/13 until 5:38....38 minutes later then with engine idle and nothing on,voltage dropped to 10 and surged to 15, at 542, the battery dropped to "0"..... with nothing on just going from park to rear to neutral tod drive on column but nothing on for about 5 seconds and came back on at 10 volts..after that no load in idle 12 volts..hope that puts an answer to this...
Expert:  Randall C replied 6 years ago.
So, the meter was bouncing all over under various load conditions? this really seems now to be pointing to a definate charging problem. One would normally see 13.8-14.2 att all times and under heaviest loads maybe? 13.5 minimum but not all over the place.I am leaning now to bad PCM. It can be scanned to conrim but witout scanner, i am going by symptoms. Below is the formal description of the system where it explains how the PCm controls all charging regulating/

The battery, starting, and charging systems operate with one another, and must be tested as a complete system. In order for the vehicle to start and charge properly, all of the components involved in these systems must perform within specifications.

When attempting to diagnose any of these systems, it is important that you keep their interdependency in mind. The diagnostic procedures used in these groups include the most basic conventional diagnostic methods to the more sophisticated On-Board Diagnostics (OBD) built into the Powertrain Control Module (PCM) . Use of an induction ammeter, Volt/ohmmeter battery charger, carbon pile rheostat (load tester), and 12-Volt test lamp may be required.

All OBD-sensed systems are monitored by the PCM. Each monitored circuit is assigned a Diagnostic Trouble Code (DTC) . The PCM wilt store a DTC in electronic memory for any failure it detects. See the On-Board Diagnostics Test - Charging System for more information.

The charging system consists of:

The charging system is turned on and off with the ignition switch. When the ignition switch is turned to the ON position, battery Voltage is applied to the generator rotor through one of the two field terminals to produce a magnetic field. The generator is driven by the engine through a serpentine belt and pulley arrangement.

The amount of DC current produced by the generator is controlled by the EVR (field control) circuitry, contained within the PCM. This circuitry is connected in series with the second rotor field terminal and ground.

All vehicles are equipped with On-Board Diagnostics (OBD) . All OBD-sensed systems, including the EVR (field control) circuitry, are monitored by the PCM. Each monitored circuit is assigned a Diagnostic Trouble Code (DTC) . The PCM will store a DTC in electronic memory for any failure it detects. See On-Board Diagnostic System Test for more information.

The generator is belt-driven by the engine. It is serviced only as a complete assembly. If the generator fails for any reason, the entire assembly must be replaced.

As the energized rotor begins to rotate within the generator, the spinning magnetic field induces a current into the windings of the stator coil. Once the generator begins producing sufficient current, it also provides the current needed to energize the rotor.

The Y type stator winding connections deliver the induced AC current to 3 positive and 3 negative diodes for rectification. From the diodes, rectified DC current is delivered to the vehicle electrical system through the generator, battery, and ground terminals.

Noise emitting from the generator may be caused by:

  • Worn, loose or defective bearings
  • Loose or defective drive pulley
  • Incorrect, worn, damaged or misadjusted drive belt
  • Loose mounting bolts
  • Misaligned drive pulley
  • Defective stator or diode

Battery Temperature Sensor
The battery temperature sensor is used to determine the battery temperature. This temperature data, along with data from monitored line Voltage, is used by the PCM to vary the battery charging rate. System Voltage will be higher at colder temperatures and is gradually reduced at warmer temperatures.

Electronic Voltage Regulator
The Electronic Voltage Regulator (EVR) is not a separate component. It is actually a Voltage regulating circuit located within the Powertrain Control Module (PCM) . The EVR is not serviced separately. If replacement is necessary, the PCM must be replaced.

Operation: The amount of DC current produced by the generator is controlled by EVR circuitry contained within the PCM. This circuitry is connected in series with the generators second rotor field terminal and its ground.

Voltage is regulated by cycling the ground path to control the strength of the rotor magnetic field. The EVR circuitry monitors system line Voltage and battery temperature (refer to Battery Temperature Sensor for more information). It then compensates and regulates generator current output accordingly.


Customer: replied 6 years ago.
Ok just got back from my garage, they put my van on the diagnostic machine and came up with possible buss line repair or bcm tech worksheet trouble codes are P1695, then no codes present on next 4 fault codes, the a number 37 system overvoltage and then P1792 battery was disconnected as last entry..Is the reprogramming something that can be done by myself? I still have no answers and no definites from you or the garage..please help...
Expert:  Randall C replied 6 years ago.
Did the shop do a charging system check on the machine? also, the codes, were they cleared and they came right back?No, you can not reprogram, need to use dealer scan tool. LMk thanks
Customer: replied 6 years ago.
Ok Tracer, here we go again, The van still has the electrical problems, but been using it because they said no problems with alternator or battery..ok this morning I went out to start it, it started ran 2-3 sec and died, it did this 3 times and then nothing. When I tried to start it, just the dash went through its lighting sequence, the radio came on but nothing..came back out an hour later and it started right up again..proceeded to go out every 1/2 hour and it started right up and electric door locks worked w remote, thats how I know its gonna start if the remote works or not, otherwise I have to enter through the passenger door and use the key. I've checked the battery, full charge..could a security code have been activated or something? Seems like theres lots n lots of posts of this similar situation on the internet...but it's not restarting this time..
Expert:  Randall C replied 6 years ago.
Your symptoms keep changing. At no point were we speaking of a no start. This has become a bit more involved that what I think I can handle. I need to opt out and let another expert help you
Customer: replied 6 years ago.
Ok.. it did stall out once when we were performing all the checks, but I neglected to mention that, because it started right back up, never stayed off, it did start back up after an hours time or so everytime yesterday, It would start, run, cut off, 3 times, then nothing for about an hour or so, then start right up and keep running, same thing last night, It started right up, so I ran to the store quickly, had no headlights or dash, just flashers, and the auto door locks kept humming when sitting at idle, I never shut it off when I got to the store, so bacically I can't go anywhere unless it starts first,and I can't shut it off because it may not start back this just adds to the electrical problem..I hear so many having the same problem with 98 caravans, and they've gone so many routes, I don't have the money to spend to replace a bcm if its not the problem, or pcm..esp if it could just be something simple..
Customer: replied 6 years ago.
OK SO CALLED experts...I found the answer, don't know how,but something I did stopped all the problems...I found out the hose coming from the radiator was disconnected from overflow tank..I fixed the hose, refilled the overflow, topped off the radiator and have not had a single problem I WILL NOT ACCEPT the answer given to me...
Expert:  Randall C replied 6 years ago.
Thanks for the information. You do not have to accept any answer given by us. Its always your call. I am sorry you are upset but your question was about flickering lights, codes and other electrical problems. I really do not understand how a radiator overflow hose cured these problems There is nothing in common with a hose and electrical problems. If you say its fixed? i am glad to hear it so sorry we could not help