Electrical dilemna - 1977 dodge van

i recently had a series of electrical mishaps, which have left me stumped. the other evening while driving home i noticed that the instrument panel lights did not come on when i turned on the headlights. i was not that concerned until i realized that the taillights were also not on. when i went to turn on the hazard lights they also would not work, except for when i had the turning signals engaged. after i got home i checked all of the lights and dashboard related items with mixed results. at final tally, the brake lights, running lights (front, side and rear), instrument panel light, the horn and the license plate light do not work. the taillights do work when in reverse and the hazard lights engage only when the turn signals are engaged.

i assumed that there was either a bad ground in circuit that runs from the back to the front, or even a break in the circuit in the steering column, but have been unable to find either and i am stumped by the instrument panel light, the horn and the front running lights.

until i figure it out, no night time driving for me.

Have you considered checking for a blown fuse?

This is a tricky one that points to a number of possibilities. Some symptoms suggest the headlight switch/rheostat, some point to the turn signal switch, others indicate bad wiring. Anything is possible with a vehicle this old. I had a '71 Chevy pickup a few years ago with taillight issues. I couldn’t find anything wrong with anything, but ended up solving the problem by rebuilding the entire wiring harness at the back of the truck. My first step in your situation would be to try plugging in a new headlight switch/rheostat and see if that changes anything. The design is prone to wear and can cause some or all of these symptoms.

Ditto on checking the fuse-- it’s probably blown, but they usually don’t go on their own. The dimmer rheostats on the old Dodge headlight switches are a pretty common problem, so that’d be a good candidate. If you take the switch out, you can look at the actual rheostat coil and check for a burnt section.

The headlight dimmer switch on the floor is another thing to look at. They are failure prone because they get stomped on and get full of mud, snow, and water, being mounted on the floor. Rusted floor pans can also cause problems for that switch.

You may be correct about a bad ground. To see if that is so you could make a long ground jumper and tie one end to the negative battery post. Then tie the other end to a good ground point near the rear lights and see if that changes things. You could also try that tieing to the a place under the dash.

Get test light probe and check for power getting to the fuses for those areas you are having trouble with. It sounds like a fusible link may be bad or a main fuse under the hood.

I know its years later, but maybe it will help someone else… But I just discovered that when my tailights were not running when the lights are on, that a green wire that runs from the a pillar next to the windshield, And wasnt running to anything when i got my hands on the van… Well, when i touch it up to the wires that have one black and one grey connector that fit together, then my tailights come back on … So, im not sure why i dont have power to that wire already, but the hot green wire got them working again? Haha good luck?!