Well Crap.

I've been having an issue w/ my brake lights staying on after I park, and this sometimes runs my battery down. I really only drive the truck on weekends, and low and behold, this past Saturday, my battery was dead. My neighbor was over shooting the breeze, so he hooked the cables up to my truck, while I drove my car around. I popped the hood on my car, hooked up the cables on my end, and turned around to notice the cables we hooked up to the truck backwards, (neg-pos, pos-neg). Damn it.

So how screwed am I?

The truck wont start, and I am getting no power inside the cab, (radio, blower, etc.) The headlights work but that's about it. I checked all the fuses, an I did find a blown ignition 7.5A, that I replaced, but still no power.

So what's next?

I'm really hoping I didn't fry my: Alternator, CPU, etc.

Please chime in guys.

 

CPU would not cause loss of power. I did this once by accident, ended up blowing up the alt. (not on this truck though).

Radio, blower etc etc needs key to be on. The lights don't. With the Ign fuse blown that doesn't surprise me. Maybe you busted the ign switch or fried some wires in that circuit. I would take a look at the wires starting at the fuse panel first for the Ign circuit. Specifically the terminals that hold the fuse in the box. Can't help you access them as I have never had to go that far into the fuse panel, but they should still be accessible.

 

check the main fuse with a tester, u probe just fried that, it will be a 60 to 100 amp one

 

if it were the fusible link, he would not have headlights like he does. At least I don't think so.

 

yes and no, i have seen it where people have rewired it where the headlights and items inside are bypassed and ran strait to batt. and headlights have there own fuses hes not saying what type of truck too so we dont know what fuses it does have.

 

if he did the headlight harness upgrade, with relays he would still need power to the truck to trip the relays. No Fuse Link = no power.

 

Yep, the 60A fusible link was blown. I replaced it, and all power is restored. That being said, Now the engine wont catch. Almost like it's not getting fuel....

For background, my truck is an '84 Sr5 pickup. I've only owned it for a few months, and I cant attest to the PO's wiring - although, it looks to be stock, other than the RED ground cable running from the battery to the engine block - I'm assuming that's what got my neighbor confused when he was hooking up the cables?

 

Update: I'm not getting any spark. (engine cranks fine, just wont start)

I have gone through the FSM troubleshooting procedure and:

1> Continuity through the ignition coil is fine.

2> Power is there on both sides of the connection to the ignitor, (I did not hook a 1.5V dry cell battery into the system, remove, and recheck power - is this necessary?

3> replaced the condensor, (used)

4> continuity at the distributor is fine

5> plug wires check out

Short of disassembling the distributor, I'm all out of ideas - any advise?

 

Mystery solved - replaced the ignitor and all is well.

The ignitor is a dealer only part - and Wow! According to my local dealer it is $500 and a 2 week wait. Fortunately, in talking with a few locals, I found a Toyota salvage yard somewhat local. $50 and she's back on the road - plus, I found a great salvage yard should anything else go belly up.

Thanks again for all the help folks.

 

You could have also gone the route of switching over to a GM module/"ignitor"

autozone I think carries the igniters too. But they arent calling them igniters, they are being called ignition control modules.

 

Ahh, good call - live and learn I guess.

I had planned on swapping in a GM alternator if I had fried mine, but I never thought about the ingitor/ ignition coil.

Is there a benefit to a "larger" ignition, or is a spark a spark? (Forgive me, I'm new to the carbeuratored world).

On a side note, while the truck is running strong, I seem to have lost my tach in the process. I was going to play with it one night this week, (since the truck is back in the garage - and out of the cold! - I'm done w/ this winter...), but advise is always welcomed. All other gauges work. Looking at the wiring diagram, it looks like the tach wiring runs through the ignition coil. Would an ignitor from a vehicle w/o a tach be missing a wire that will need be be spliced in?

All in all, I'm just really happy I didnt fry the computer. Thanks!

 

No real benifit from the GM ignition module swap, just cost to repair. There is a really good write up on pirate for that as well.

quite possibly yes on the tach as that wire comes off the igniter. Not sure on the wire color though I wanna say black but these might help:

 

also forgot, did the igniter come off a carb'd truck or an EFI truck?

 

The donor ignitor came off of a carbed '84 - I didn't think to check if it had a tach. It was a 2wd though, although I doubt that matters.

That wiring diagram in the back of the FSM is/was a lifesaver! I have ZERO electrical experience, but w/ the diagram, it's a pretty straight forward loop.

 

as far as the brake lights staying on, a friend of mine had this same problem and it was the brake switch sticking. Try replacing that and see if you can save your battery from certain death!