[CBizkit84S]

Hey I am new here and I am in need of help to better understand my truck. I have no headlights, tail lights, spedometer, or horn. While trying to trouble shoot and test wires, I no longer am able to get it to turn over. I have restored the interior 85%. Had to remove the bed to get to a seam behind the cab that was the cause of a leak (hence the interior restoration). Didn't want to put the bed back on until I figured out the problem. Things I have done so far are replace the:

Distributor cap and rotor
Spark plugs and wires
Fuel pump
Fuel filter
Crank case breather
PCV valve
Power steering lines (both the pressure and return)
Flushed the coolant system
Air filter

With all of this, I cannot see the reason why this would be a lost cause. Does the bed not being connected to the ground have anything to do with this? Am I missing something? Am I to just replace the entire wiring harness? Please let me know what your thoughts could be.

 

[radioactive]

Removing the bed should not cause your problem. You just need to take a methodical approach to troubleshooting. Does it crank? (You said it doesn't turn over.. just want clarity) Do you have dash lights? Get the correct wiring diagram and start tracing voltage... It seems like you've blown one or more fuses, or dislodged a connector or relay. Go with the basics.

Replacing the harness would be a desperation move that is not warranted unless you've really badly damaged it when pulling the bed. But keep in mind that there is little mission-critical wiring running back there. Just the fuel pump.

There's very little between the keyswitch and the starter solenoid in these trucks. There is a controlled relay, do you hear it click? Do you have voltage at the solenoid? Does the pump run at key-on? What's your battery voltage? is there a fusible link intact?

 

[CBizkit84S]

Those are excellent questions.

I do not believe I have checked the solenoid. I'll do that when I get home.

I'm getting 12v as I should

I bought the online Haynes manual that gives "Typical wiring diagrams". However, I do not know if there's one for my specific model. So I'm using it as a reference only.

Nothing was damaged when removing the bed.

All fuses are intact and not blown. I do suspect the relay was fried. I'll be picking that up on my way home from work. Fusible links... can't find them but the diagram shows they exist?

The ignition is getting power but won't turn the starter. That's why I'm suspecting the relay.

Lighting: ok so i was getting the dash lights. After replacing the headlight switch, I would get my running/parking lights. As soon as I pull the switch all the way back, the lights go off altogether. No headlights and no taillights. Have not been able to test if the speedometer is still out but I suspect if all this gets fixed, then so will that.

I'm not a mechanic but I'm mechanically inclined and help build jetliners so I'm making sure to be just as methodical and careful as I would as work. I'm not offended by your questioning. Just wanted to make aware my novice level when dealing with automobiles. I know more about my bicycle than I do my truck hahaha. I'm learning as I go though so I can teach my kids so they're not in my position when they're my age.

 

[radioactive]

Fusible links are typically in the battery cabling. I believe my year only has 1. It's generally a short section of wire covered in heat shrink -- 1/2 the diameter of the wire it is protecting.

You hadn't mentioned earlier that you'd replaced the headlight switch. That means you've been behind the dash. I'd take a look and see if you've dislodged any connectors back there.

The lighting symptoms -- might indicate a bad ground or bad connection. Try and pull too much current and it effectively goes open.

Did the no-crank scenario start when doing all this work -- or was it a problem before the big list of stuff you've tried? (None of which are capable of causing a no-crank scenario).

By the way -- 12 volts is too low. If you're not seeing 13.5 or higher, try a known good, charged battery asap. Everyone says 12V when they work on cars, but in reality the systems run higher. Measure the battery voltage when you attempt to crank. And again down at the solenoid if you can, might require a helper.

If there is a ground bundle/ring terminal that was bolted to the bed (I can't envision this being the case) be sure and bolt it to the frame for now.

I wish my kid had taken an interest in cars. Best I could do was teach her how to check her oil and change a tire -- a skill she actually had to use once!

 

[CBizkit84S]

Fusable links: I will check again for this when I get home.

Headlight Switch: I will double check to make sure all connectors are snug. This replacement was a thought to remedy the problem. It wasn't until after that I got my running lights back but then goes out when fully switched on for my lights.

Cranking Issue: This became a problem after the fact. Relays were pulled and it might have been fried in the process of checking everything.

Solenoid and Battery: I will get this tested when I get home. I will also get a brand new battery to be sure I'm getting full power. I've been getting help from my brother-in-law. He's more knowledgeable about working on vehicles but even he's stumped by the electrical problem. So I'm seeking advice from people like you.

Ground: There are two ground cables that are bolted to the cab that go to one bolt on the bed. I'll get that put back on today. I just wanted to make sure I wasn't going to block myself access to something important. I see now that I'm not.

I appreciate you taking the time to help me understand this better.

 

[radioactive]

The cab-to-bed wires you are describing sound like simple static grounds, but if you can tie those to the frame for now (bed still off?) then that will eliminate any missing ground scenario caused by you removing the bed. Doesn't necessarily eliminate all potential ground problems.

How long has the truck been inoperative?
How old is the battery, and what is the open-circuit voltage? (Use a meter not a test light) What is the ambient temperature there?
Now, what does the battery voltage drop to during crank attempt? It could be too low to even pull in the solenoid.
Has the radio lost its' presets? Does it power on in ACC position? Is it affected when you try and turn on the headlights?

All these things are clues. (You don't need to answer all that, those are meant as guidance and may not be meaningful. The more I think about this, the more I feel like it's a battery issue. But I've been wrong almost as often as I've been right -- especially in a remote diagnosis.

Was the engine healthy before this? Can you turn it over with a big socket on the crank pulley nut? Might have to pull the spark plugs to try that.... so proceed carefully.

Does the truck have any sort of security system, remote start, OEM or aftermarket?

Resolve your relay situation (I'm betting they are OK) and go after the battery possibilities. Keep us posted.

 

[CBizkit84S]

Ok update: Found the neutral switch disconnected at the transmission. That was the cause of it not starting all of a sudden. Now that issue is resolved.

Need to now find out why I am not getting my headlights, taillights, horn, and speedometer (again won't know if that is fixed until I drive it).

 

[CBizkit84S]

I have not altered anything outside of just replacing stock components with exact replacements. No security system or the like had been installed. No remote start either.

We are going to chase the wires back from the headlights and see where that leads.

 

[radioactive]

Now that you've solved the no-crank problem, none of my suggestions apply. I assume it runs now?

From here, the lights should be straight-forward troubleshooting. In your gen Dakota, I don't believe any controllers are in the path of the lights. Should be as simple as a switch, fuse, and a relay or two.

 

[CBizkit84S]

Yes it runs now.

I believe you are correct with the lights.

 

[CBizkit84S]

I FOUND THE PROBLEM!!! Damn it that took forever! Thought I was never gonna find it....geeze

 

[radioactive]

Good work!

 

[CBizkit84S]

Good work!

Hahaha thanks. I appreciate the talk over this all. I was quite helpful. Do you know if all first gen Dakotas have the same bulkhead fitting?

 

[radioactive]

I do not. But replacing that entire connector might be quite the chore. If it were me, I'd be tempted to do a work-around for that wire. Run it external to the connector, thru a nearby hole, or such... the truck is almost 35 years old.... But if you want to tackle it more power to ya.... Junkyard trip.

 

[CBizkit84S]

Lmao true true...I was only looking to take the one connector end out and have only 1 splice. I do have a junk yard 2 minutes from my house that has a 90 and 92 I was going to check. That idea you proposed was going to be my alternate plan.

 

[CBizkit84S]

Junk yard ftw! I just pulled the whole fitting from a 1990 manual so the wiring is different. I pulled the "50 way bulkhead disconnect" from another thread here posted back in 2017. I cannot find one for the 1990. I know they are similar but some things I may have to go without for the time being...

that being said, how important is the overdrive? Is it a function critical component, or will I be fine without it?

 

[CBizkit84S]

Ok so latest update:
I have replaced the bulkhead disconnect and it went flawlessly. Now I am trying to tackle a new problem I am having. Where can I find a complete diagram for the coolant system? I am wanting to replace a few parts but need to understand that system more. Any ideas?

 

[immattj]

RalphP put a PDF in a thread on another site; maybe it will be of some help:

Can some one explain the cooling system flow direction...

I have what looks like a fairly new water pump off my 3.9 V6 core engine. I have looked at the pump and it appears the pump pulls coolant from the rad and the by pass just next to the thermostat and outlet. If someone can explain or has a link to a good article share. Steve

www.dakotaforumz.com

 

[CBizkit84S]

RalphP put a PDF in a thread on another site; maybe it will be of some help:

Can some one explain the cooling system flow direction...

I have what looks like a fairly new water pump off my 3.9 V6 core engine. I have looked at the pump and it appears the pump pulls coolant from the rad and the by pass just next to the thermostat and outlet. If someone can explain or has a link to a good article share. Steve

www.dakotaforumz.com

This is exactly what I needed to see. Thank you. I too need to find a service manual for my truck. Thanks again.

 

[immattj]

A little while ago I finally broke down & got a full 4 book (because I prefer paper to disc) FSM set for mine off of Ebay for under $80.

Ralph, on the other hand, prefers disc & he frequently posts this site:

Bishko Books, Repair Manuals, Owners Manuals, Parts Books & Sales Brochures (autobooksbishko.com)