Hi all. Been running into issues lately and was hoping someone might be able to shed some light (sorry for the wall of text lol)

I have an 89 Dakota Sport (3.9l v6) with 120k miles on it which runs fine.

Last week I started it up as normal but I had no head lights, tail lights, brake lights, horn, no 'you forgot your key and opened the door' buzzer, interior dash lights. overhead interior light, dash warning lights, turn signals and reverse all still work as does radio and seatbelt buzzer.

When I start it the ABS and Brake warning lights come on for about 10 seconds then go off but both came back on whenever I tried to turn on headlights or stepped on the brake (which also caused my rev-ometer to die) than 10 more seconds and they would go off again but as of a few days ago the ABS+brake lights stay on and rev meter doesn't work.

I checked all the fuses in the fuse box under the driver side dash (theres only 1 right?) and no issues.
Stripped and replaced the battery post terminals, on the positive end the 2 red ones were fine and shiny but the black one had some blue chalk in it so I cleaned it up best I could. On the negative end the fat black cable also had the same blue chalk.
I opened the fat plug that goes unto the firewall and there was some blueish residue on a couple of the pins so cleaned them up with battery terminal spray. I did a voltmeter test and a few didn't produce much voltage (~3 volts) and the meter gave a 'Bad' reading.
On the other side of the firewall, where the fat plug wires come out and go to fuse box/wherever I could see some of the blue stuff. Did I continuity test on it to the fuse and it checked out.
Still no luck

Took it in to a shop and after checking it for 20mins he said he'd have to charge me by the hr and try to figure out where the issue was as he believed it was a short.
My biggest issue is having no brake lights cause I need to use truck for the next couple of weeks. A temporary fix would be great till I can get it into a shop.

Might be irrelevant but:
A few years ago it got burried under a bunch of snow and after getting it out the ABS brake warning light started coming on but I just carried on using it (busted sensor I assumed).

a year ago the AC stopped producing cold air. The AC switch would light up but no difference in air temp being blown in.

A couple months ago the interior lights got left on and the battery died. Got a jump, drove around for a a bit and all was good after except for the occasional sluggish start causing the radio to lose memory.

 

I had the exact same problem with my 89 sport. I checked all the fuses and feed wires on the back of the fuse panel, but everything seemed fine. It turned out that the fat plug had corroded (the dreaded blue stuff) really bad on the engine side of the firewall and shorted out. I just had to clean the contacts really well with some sandpaper and remove all the corrosion from both sides of the plug before everything started working again. The tab for main feed wire (red with white I think) was so corroded that after I cleaned it, it was too thin to make contact with the socket, and I had to bend it. You might have to mess with one of the tabs you cleaned.

 

Thank you so much Mirado. I'll grab some sandpaper on the way home and do this tonight!

 

Brake Cleaner and dielectric grease, too.

 

Never worked with it but added to the list!

I assume,
1. sand contacts to take off corrosion
2. apply cleaner then wipe off
3. spread on grease and reconnect
?

 

cleaned them all and applied the grease but still no luck

Just before I applied the grease I tested the voltage on each of them and has a few that didn't register anything at all, a few that hit 9, a few that registered more than 9.5 (small multimeter ) as well as 1 that did 5.7, 2 @ 3.5 & 3 @ 0.37 volts.. that seems too low right? am I supposed to get the same voltage on all the connected ones?
FYI, I didn't have the key in the truck but not sure if that would've made a difference (1 end of meter was at positive battery post and the other touching the pads)

I do have the readout from each pin if that would help figure out whats going on.

I also cut back the black battery cables (1 from positive and 1 from negative) but didn't matter how far back I went its still caked in the chalky blue stuff

Based on this, I'm guessing I need to replace the fat black wires coming out of the battery? Is that something difficult (I'm a novice lol) also, where can I get the cables?

Thanks again guys

 

I'm having almost same issue with my '93. Headlights not working, but parking lights come on. I'll go outside right now to try a few things and post back what I find. We've got to figure this one out!

 

Ok, no luck. I took the thingamabob this: off, but all wires looked good. It is held on by a long bolt, and wrapped good with electrical tape. The rubber boot rolls back easy with tape off. Still trying to find why headlights won't work.

 

It looks MUCH cleaner than mine so may not be the issue. Is it just your headlights that aren't working?

For me its head, tail, brake and interior dash lights that don't work. Also no horn, or RPM gauge and both the ABS and emergency brake warning lights always on.

Have ya checked the fuses?

 

I have had the same issue with my '89 Dakota. My problem was corrosion in the main power feed to the lighting system. I have repaired it as follows:

There is a main wiring connector on the left side firewall, near the brake system master cylinder. This is fastened by a bolt. Peel back the rubber boot and you can remove the nut and then unplug the main connecter. the lighting should be in one corner of the connector and I believe that it is a red wire with a white stripe. You can disassemble the connector by prying out and removing the blue colored keeper. The spade terminals have a square hole and there is a black plastic tab that retains the spade terminal in the connector assembly. Pry back the black tab and the spade terminal can be pushed out of the connector ( you will have to remove some of the electrical tape from the front of the main connector.

There is probably some corrosion on the connection of the wire to the spade terminal and also corrosion inside the insulation of the wire.

I was able to find some of those OEM spade terminals through the Carquest dealer. I cut the old terminal and about three inches of wire off of the red/white wire. I soldered a new terminal onto a piece of 10 Gauge Primary wire and then I spliced this
new end onto the red/white wire and then I reassembled everything.

Hope this helps.

Dave