2nd Gen Non-Engine/Transmission flickering head/dash lights

[fhoward]

96 2500 2x4 pretty standard truck with flickering headlights and dashlights. have replaced the multi function (turn signal) switch and headlight switch with no change in symptoms. is not the grid heater.

a small wiggle can be seen on the amp meter as well. have thought that i'm partially loosing the ground or a relay is failing. it also is intermittant in that it may not flicker for an hour or two and the next trip it will be constant for the duration of the trip. my concern is that the lights may simply quit and with my luck would be on a curve, etc.

i sure hope this looks familiar to someone with the cure !!!!!!!

 

[DPellegrin]

I had that problem for a bit also I have the same exact truck it turned out being my air temp sensor it just screws in the top of the engine I think it cost me $40 from the local cummins the voltmeter on the dash just moves really quickly and returns to normal lights flickerd also.

 

[BigPapa]

I just had to replace the passenger side headlight bulb socket. It had a short in it. It didn't effect the dash illumination but it sure messed up my headlights and my driving lights I have wired into the headlights via a relay. It would be fine for a while and then it would flare up.



Scott

 

[fest3er]

96 2500 2x4 pretty standard truck with flickering headlights and dashlights. have replaced the multi function (turn signal) switch and headlight switch with no change in symptoms. is not the grid heater.

a small wiggle can be seen on the amp meter as well. have thought that i'm partially loosing the ground or a relay is failing. it also is intermittant in that it may not flicker for an hour or two and the next trip it will be constant for the duration of the trip. my concern is that the lights may simply quit and with my luck would be on a curve, etc.

i sure hope this looks familiar to someone with the cure !!!!!!!

Sure sounds like the grid heater relays. Questions:

• Is the flickering a 'momentary' dimming of the lights?
• Is it worse when you drive over rough-ish roads, and not so bad when you drive on smooth roads?
• Does the flickering seem to be 'randomly' timed?

If you answered yes to both, your intake heater relays (one or both) are failing, and you can expect one of them to 'stick' on sometime, draining the batteries and melting stuff. Remember, each heater draws about 100 amps. Specifically, the failure is that the internal spring that is supposed to keep the contactor away from the contacts has weakened over time; thus the contactor bounces against the contacts, causing moments of high current draw, resulting in the flickering you see.



To prove or disprove that the heater relays are the cause, I think you can disconnect the lead that goes down to the relays from the left battery positive terminal. If the flickering stops, you know it's the relays.



A link to my solution:

http://murent.us/dodge-heater-relay/

It's been five years now, and the Stancor relays I used are still behaving like new. I have to say they've turned out to be far better than the OEM relays. Some folks may have used the Stancor 120-901 relays, but I opted to use heavier-duty relays (Stancor 120-902).



Also, you can search the TDR fora for 'stancor' for more information.



Neal

 

[MrDiesel]

On my 97 it was a loose connection at the relays. I checked the heater grid 3 times before I figured out the connection was just not quite strong enough at the trigger wire on the relay with the vibration of driving the truck...

 

[CumminsPower98]

On mine it was the fuel heater/thermostat harness. Both were fried and the wire in the thermostat was just hanging loose and would make contact sometimes and cause the lights to dim slightly.

 

[fhoward]

neal,

thankx for the direction, would never have thought to ck the grid relays (got to find them), it's 0 deg outside, will pop the hood when it warms up a little and explore. the problem has existed for over 1 year, farmed last year with old chev truck and this one sat alot.

fritz

 

[fhoward]

major thankx, turned out to be the left hand 90 deg push on wire on the rear grid heater relay. was a matter of compressing the connector with pliers slightly and pushing the connector back onto the post. can't get more simple (the kind i like).

again, thank you



fritz

 

[MrDiesel]

You're welcome!