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2nd Gen Ram Tech1994-2001 Rams: This section is for TECHNICAL discussions only, that involve the 1994 through 2001 Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
Headlights not working unless I keep the combo-switch pulled back (e.g., flash-to-pass). Dash pull switch and combo switch have been replaced. What else do I need to look at?
Seeing many people are having trouble with wiring harness and, I suspect that might be my problem as well, does anyone have any experience using the Formula-J87 9004 wiring harness? Do you think this thing will help?
You can download the factory service manual for your truck from here. Wiring diagrams are in section 8W. Have a look at the headlight wiring. That will tell ya where power should be when. These trucks are notorious for smoking the headlight switch/harness connector though.... So, may wanna check that first.
Formula-J87 Relay Wire Harness 40A 9004 HB1 Head Light Adapter High Heat Replace Ceramic Fit https://www.ebay.com/itm/143342949942
(image upload didn't work for me)
Formula-J87 Relay Wire Harness 40A 9004 HB1 Head Light Adapter High Heat Replace Ceramic Fit https://www.ebay.com/itm/143342949942
(image upload didn't work for me)
A good relayed headlight harness is helpful after taking care of the headlight wiring harness that plugs into the headlight switch in the dash. That wiring and their electrical connectors going to the headlight switch are famous for getting hot and failing.
Formula-J87 Relay Wire Harness 40A 9004 HB1 Head Light Adapter High Heat Replace Ceramic Fit https://www.ebay.com/itm/143342949942
(image upload didn't work for me)
Not familiar with this exact product, but in general a relay harness is a great addition, however, if you already don't have power to the lights, The relay harness will provide no remedy to the situation.
The switch/harness is a great start for investigating the problem 94-98 pull style switches are common here.
Is this a new to you truck? Did you recently replace bulbs. Using the wrong headlight bulb can produce this scenario due to the pluggin being the same but the pinouts being different.
That harness will take the load off the switch for the headlights but doesn't do anything for the running lights. I have replaced mine(headlight switch and pig tail) twice because of melting. I wanted to change all my bulbs to led but never got around to it. That will drop the load significantly.
Not familiar with this exact product, but in general a relay harness is a great addition, however, if you already don't have power to the lights, The relay harness will provide no remedy to the situation.
The switch/harness is a great start for investigating the problem 94-98 pull style switches are common here.
Is this a new to you truck? Did you recently replace bulbs. Using the wrong headlight bulb can produce this scenario due to the pluggin being the same but the pinouts being different.
The headlights do come on, but only while the combo switch is pulled in.
Truck is 'new to me,' but the headlights used to work fine and the bulbs haven't been changed (yet), so pinout difference can be ruled out.
The dash headlight switch and combo switch have been replaced.
That wiring harness I mentioned at the top is on the way and... I sure do hope it takes care of the problem.
The headlight harness that plugs into the headlight switch (as shown in the photo on the left) is where the wiring regularly heats up and fails, either with loose connectors in the plastic connector (from heat) or melted wiring. The relay harness will not fix this issue.
The headlight harness that plugs into the headlight switch (as shown in the photo on the left) is where the wiring regularly heats up and fails, either with loose connectors in the plastic connector (from heat) or melted wiring. The relay harness will not fix this issue.
Im not sure if its by luck but every headlight switch ive bought for these trucks in the last 10 or 15 years has came with the harness pigtail. Maybe I just got lucky getting a "kit" instead of just the switch.
Im not sure if its by luck but every headlight switch ive bought for these trucks in the last 10 or 15 years has came with the harness pigtail. Maybe I just got lucky getting a "kit" instead of just the switch.
On RockAuto's site, I believe they only list one headlight switch listing that has the headlight wiring harness included. Before long, I suspect the harness will be something you may have to buy separately from the switch, in today's inflationary times..
Headlights not working
