Engine/Transmission (1994 - 1998) Electrical problems

[rnolen]

Just a little while ago my lights started flickering. They are not at the point were they are going out but just flickering. This is not the normal grid heater draw either. There is not ryme or reason to it. I started looking at everything and noticed corrosion on the both of the battery terminal wireharnesses. It is all the way in the wires on these harenesses. Would this gause this problem? I checked the headlight switch and it looked ok. How do I test if it is my grid heaters or not. I put a new solenoid on it about 20000 ago. Could it be the altenator and is there a way to check that. If it is the voltage regulator do I have to replace the PCM and is there a way to check that as well. I love this truck but lately it has been non stop trouble. Although before I had about 30,000 trouble free miles.



Thanks in advance



Russ

 

[crabman]

rnolen,

Is it your head lights? Are they going dim? Or just flickering?

Multifunction headlight switch maybe your problem.

Clean all the battery terminals. You can get some of the corrosion off the wires by using cola or a paste of baking soda and flush with clean water. Clean the ground cable points on the engine also.

What is your voltmeter doing on the dash? Is it showing a constant voltage(14V)? If so, then the alt. is not the problem.

Do a search on the multifunction headlight switch.



My h/l switch just triggers a set of relays which in turn draws all the power directly from the batteries which bypasses the inadequate factory wiring.

Try all the above and post your results.

crabman

 

[rnolen]

All of my lights are flickering. My volmeter fluctuates as well. It is not a regulated flickering, like when your grid heaters come on. I have cleaned the terminals and in fact replaced the negative cable from battery to battery. It was cheap compared to the harness for the positive. Can the head light switch be bad and still look ok? I thought it was the heat that killed them and you could see were it had melted. How do I check for the grid heater malfunctioning? How do I diagnose that what it is. Is there a way to check and see if your alternator is bad? If it is the voltage regulator do I have to replace the PCM. How much is a PCM for a 97. I am trying to learn more on diagnosing and fixing my own problems and electrical is definately not my strong point.



Thanks



Russ

 

[crabman]

Tests

Here are some tests for the heater & relays:

Heater Test

1. Disconnect both neg. battery cables.

2. Lift the rubber shields from each of the cable connectors at the intake manifold air heater. Do not disconnect cable nuts.

3. Use an ohmmeter to test the resistence between cable terminal and a ground. Should be zero. If not zero, check for corroded wires, etc. and clean, & recheck.

4. Disconnect both cables from the IMH. (2 nuts)

5. Measure resistance between from each terminal to a ground. Should be zero. If is is anything other than zero, replace IMAH.

6. Reconnect wires to IMAH if it passes all the tests but not neg. batt. cables.



IMAH Relay Test

1. Disconnect the 4 small relay trigger wires at both relays. Note position of wires before removal.

2. Disconnect the 4 large cables at each of the relay terminals . (4 nuts) Also note position of cables before removal.

3. Attach ohmmeter across 2 of the large studs on ONE of the relays.

4. Attach a jumper wire (+ and -) to each of the small terminals on one of the relays. Polarity is not important.

5. Monentarily touch the jumper wires to the vehicle battery (+ and -). The relay should click and the ohmmeter should show a closed circuit across the large terminals. If not, relace relay.

6. Repeat the same test for the other relay.

7. If relays pass all tests, reconnect wiring in the proper positions.



For peace of mind, I would remove the alternator and have it bench checked. Be sure to disconnect neg. battery cables before or you can blow the 120 amp fuse in the PDB on d/s fender.

Good Luck!!

crabman

 

[crabman]

Service Manuals

Service manuals can be bought from Chrysler. 1-800-890-4038 M-F 8-4:30, E. S. T. , cost about $90.

Or online at www.techauthority.com about the same amount of $$.

crabman