Electrical nightmare

[WahooSteeler]

Well I guess I was due at some point for a headache or two of problems, after all it IS a Jeep, and it does have 200k. So here's my first and I'm looking for help from the electrical specialists here.

 

For the last few months I've actually been driving around with most of my dash pulled apart, electrical components hanging everywhere. ECM, Trans computer, cig lighter, clock, you name it. I took it all apart to install a new radio and to go through all the dash and back lights. Some of you may recall I posted a thread that recently the clock went out, but what was interesting was that there was power to the backlight, just not the clock itself. I still have not installed the radio either because about the same time, I was unable to get it to power up anymore. Previously I had only done a brief connection of the power leads to make sure it powered up (bought used off eBay). I spent several hours two weekends ago looking for potential problems with no luck. As noted in my clock thread before, all fuses are good.

 

So there is some history, and now the back-breaker. I was hauling trash yesterday and when I get back in to go and turn the key........nothing. Not a turn, not a click, nothing. Fortunately my Pop was able to come jump me. Get home, let it run for another 15 mins, shut it down. Come back later and as I expected, no start. So I grab my jump box and let it juice for about 10 mins before I try to turn it. Nothing. Hook it up to the wife's car, let it run a good long time, and basically it will either give me a click or all the interior lights will go out, i.e. not a drop of juice anywhere. Sooooo, my guess is I've got a short drawing it down or loose ground somewhere. What I REALLY think is that it is something in the ignition because power seems to cut in and out a lot when I go to turn the key.

 

Whew.....a lot of info, I know, but I'd rather give as much up front to help get a diagnosis. Ready for your suggestions...... :popcorn:

[Eagle]

First, Grasshopper, eliminate the obvious.

 

It is tempting, since you've been mucking around with wiring, to assume there's a wiring problem. But ... at 200,000 miles, your alternator is definitely past it's projected life span. I would first test the alternator to be sure it's producing enough current to keep the battery charged. Don't forget, you're running an electric fuel pump and electicrally-fired fuel injectors, as well as the ignition coil. All that sucks out a lot of power in a few miles.

 

If the alternator checks out, then check to be sure the battery will take and hold a charge. In fact, maybe reverse it -- check the battery first, and then test the alternator if the battery is good.

[comanche87]

i agree with eagle.

[WahooSteeler]

I thought of those things and will do, but what doesn't add up there is that I made two differet stops before the trash run and it fired right both times.

 

Also as I said, sometimes as soon as I turn the key, the power cuts out. I.E., interior lights on, turn key to "on" position, everything goes dead BEFORE I even try to turn it over. Now, several times I checked to make sure it was all the way in Park, which it was, but would pull it back to N and then to P again to make sure. A couple of times the lights and door/key buzzer would fire back up while doing this, and then die when I turned the key to the on position again. Hmmm, just realized, NSB switch maybe?

 

Battery "appears" to be fairly new from what I can tell.

 

I guess the other thing to add is the PO had stuff wired all over the place. Fog lights, light inside the cap, etc., which has all since been removed. It appears he also re-wired the aux fan himself as I see half of a factory pigtail in that area and what is clearly add-on wiring after that (although it works great). Worse though, many of his additions he used those blue in-line connectors and straight up splice and dice w/nothing more than electrical tape.

[chicofuentes0224]

So basically you can't get it to Autozone or an equivalent to have em check the battery and alternator right?

[WahooSteeler]

Battery I can pull, alternator a little more involved since I have to remove the front skid plate etc.

 

If I get lucky and get it to start again, I can drive to Advance Auto since they are in the same shopping center as my office. And since we are the property mgr's for the shopping center, I won't get towed if it has to sit for a couple of days! :brows: Hell, across the lot is a vacant muffler shop that I could even push it in to, worst case, to do the work if the alternator needs replacing.

 

I'm thinking that may be a good possibility since I've had the squeeling belts for several months now also, and it increases with RPMs. I may be wrong, but that still doesn't seem to explain the instant "cut-in cut-out" of the juice to me.

[Eagle]

Losing everything when the ignition switch is in the ON position rather than the START position makes it sound like there's something amiss with the ignition switch. Which is NOT at the key -- they key is only a tumbler mechanism, the actual electrical components are in a switch module at the base of the steering column.

 

What about headlights? Do you also lose headlights when the key is turned on?

 

If you plan to keep this truck for any length of time, it might be worthwhile getting a complete wiring harness from a junkyard and starting over. Inherited problems due to jackass wiring are exceedingly frustrating, and you never know when the next one is going to bite you in the posterior.

[WahooSteeler]

I'll troubleshoot again this evening, but now I'm thinking if I got it to "power up" it was ok when in the "on" position but as soon as I turned to start, it went dead. Again, I'll confirm tonight.

 

Is the ignition module easy to access? Please say yes.......

[Boilermaker]

If you plan to keep this truck for any length of time, it might be worthwhile getting a complete wiring harness from a junkyard and starting over. Inherited problems due to jackass wiring are exceedingly frustrating, and you never know when the next one is going to bite you in the posterior.

I'm in a similar situation, and Eagle's suggestion about a new dash harness is the way i'm going to go. The PO put in an aftermarket stereo, amp and alarm and the harness is hacked up. The alarm would go off while i was driving. I tried to replace the dummy panel with a known good clock and it wouldn't work. I've also been driving around without a dash while i work on the interior and it's taking a little longer each time to start. The battery and the alternator have been tested good and troubleshooting the hacked up harness seems to be a waste of time.

 

I look at is as another excuse to work on the truck. A dash harness from a loaded 2 door 92 XJ would help with a clean install for power doors, window and mirrors.

[brigarpeon]

To check the battery just put a multimeter set at 12V, across the terminals it should carry a 13.2 to 13.7+ volt charge. If it reads under 13 volts then (A) The battery is not being recharged by the alternator, (B) The battery has an internal short and can not recieve a charge. If the battery reads 13.2 an above; jump the truck and remove the hot + terminal. If the truck stalls then the alternator is not charging the system. This can be from multiple reasons but first take your multimeter under the truck and check the field output of the alternator. The output should be 13.7 to 14.2 volts less than that replace the alternator. If you check out at 13.7 to 14.2 at the the alternator output then you need to check the fusible links at the starter relay under the hood on the passsennger side fenderwell behind the headlights. The large gauge red wire with the blue fusible link actuates the alternator. The last thing I can think of would be the B+ LATCH relay on the passenger side fender well, mine only has 2 relays, one is the fuel pump relay the other is the B+ Latch key relay.

 

I SERIOUSLY DOUBT IT'S THE IGNITION MODULE

 

As far as the clock/radio issue goes there is an in line 5amp fuse in the violet/orange wire that feeds from the harness Variety LTS that could be blown. This in line fuse is in addition to the radio fuse and the clock fuse bringing the total to 3 fuses.

[WahooSteeler]

I'd be all for replacing the harness, but I'm sure that's a project a little beyond my reach, if not the contents of my tool box at the very least. And considering the amount of time to do that, it's not something I want done at $65/hour either.

 

Plus, I'm leary of grabbing a JY harness, but I'd be willing to follow the general consensus here. I would just worry that after going through all of that the JY harness would crap out too.

[chicofuentes0224]

Replacing the dash harness is easy. All you need to do is take apart the whole dash :D The good news is you don't need any special tools. Just a screwdriver and a couple sockets. Yu'll need a marker, tape, and baggies so you can mark and remember where everything goes after you pull the old one out. TAKE LOTS OF GOOD PICTURES AS YOU PULL THE OLD ONE OUT. I didn't and it took me about 100 hours to replace the dash and engine harness because I had no idea where anything went. Seriously though, if I had to do it again I could probably do it in three to four hours. And that's with absolutely no mechanical experience or patience.

[WahooSteeler]

Good to know. I started thinking about that potential project more after my last post. First of all, I'm halfway torn down now. Second of all, I realized how easy it was to get to the halfway point. Where I'm more concerned (ok, more lazy I guess since I am also impatient with stuff like this) is in the engine bay.

 

Overall I think I'm fairly mechanically inclined. When I raced motocross I used to do all the work on the bike myself, top ends, suspension etc., so it's probably more just digging in to it.

 

I just remembered my son has T-ball team pics tonight and I need to cut the grass something fierce, so I probably won't get and diagnostic time tonight. Keep the suggestions coming, I'd rather have the laundry list already filled out so when I start I can just start checking stuff off.....

[Eagle]

Wahoo, does your '88 still have the big C101 connector? If so, it'll be a LARGE electrical connector block high on the firewall inside the engine bay, directly in front of the driver. All '88s had it. There was a TSB out for cutting it out and splicing all the wires -- if yours has been updated, you'll have a metal tab/shelf there that looks like a mistake 'cause it's not holding anything. That's where the C101 connector goes.

 

The point being -- if you still have the C101 connector, your dash harness is completely separate from your engine room harness. You can replace one without touching the other. Actually, I think the dash harness may be separate even without the C101 but I haven't gotten that deep into the under-dash wiring yet.

[WahooSteeler]

I'll check Sensai. I think I'll take some detailed pics to post to get an idea of what's what.

 

I've also started searching for an electrical FSM on ebay and forums.

[chicofuentes0224]

Personally Dubya, I still think it's the battery or the alternator. If you can't or don't feel like running the tests, go to Wal-mart. Buy a cheap battery and put it in. If the truck works and dies later you know it's the alternator. If it doesn't even start with the new battery you can always just take it back to Wal-Mart and get your money back and then start looking for crazy electrical problems. I agree w/ Eagles first post that you might as well get the obvious crap outta the way before you start stressing yourself out with the other crap.

[WahooSteeler]

Oh absolutely on checking these two items first. Battery is easy, and the skid plate is just a few bolts so getting to the alternator really isn't that bad. Now that I've vented and gotten some feedback I just need to lay my fat @$$ on the ground and start messing with it. Pulling the skid plate will help me clean all the gunk down there anyway. Hell, I'm begging it's as simple as one of those two!

 

My bet is alternator since I've had undiagnosed belt/pulley squeal also.

[mjeff87]

you can wiggle the alt out from the bottom with the skid in place.....ain't easy, but it's doable. Either that or pull the battery and the battery tray and pull it from the top.

 

My preference is from the bottom, though....

 

Jeff

[Eagle]

I'll check Sensai. I think I'll take some detailed pics to post to get an idea of what's what.

 

I've also started searching for an electrical FSM on ebay and forums.

Good luck. The 1988 electrical manual is a separate book, it's fairly large (although not as large as a full FSM), and even my dealer doesn't have one. And they were selling Jeeps back in 1988.

[brigarpeon]

My bet is alternator since I've had undiagnosed belt/pulley squeal also.

Maybe it's just the belt or it tauntness then.

[WahooSteeler]

It's good and tight and I've sprayed belt conditioner on it several times. Stops or quiets down for maybe 30 mins then comes back.

[brigarpeon]

It's good and tight and I've sprayed belt conditioner on it several times. Stops or quiets down for maybe 30 mins then comes back.

Start the truck and pull the positive off, if it shuts down the alternator is shot.

[WahooSteeler]

Yup, saw where you posted that before. Just remember one problem, it won't even start on a jump now, hence me thinking it's a jump or ground issue...................or ignition.

[WahooSteeler]

Good and not so bad news.

 

Had a chance to fiddle around with my electrical issue this past weekend. So the good news is I got the clock and radio working! Yeah! (JT, want your clock back LOL?) Homer Simpson here overlooked a power lead that had slipped behind the HVAC controls, so I was only hooking up the battery lead to the battery and power lead on the deck. DOH!

 

The not so bad news is I think I've identified the no start/dead battery issue also, to some extent. While tracing wires around the engine bay, I re-confirmed for the 100th time that the PO was all about "The Splice". I have never seen so many "tap and go" hookups, i.e. he would just splice in to any fused power source "mid wire" with electrical tape to hook up whatever he was running. Anyway, there is a power block or relay of some sort just behind the battery with several wires attached with spade connectors. When I grabbed each wire around it to see if there were any loose connections, they were all tight but whaddaya know, lights and electric fan came on. Buuuuuttt, it still needed to be jump via cables (jump box still not enough juice) and after running for 30+ mins, no start again immediately after turning it off. So, tomorrow I hope to post a pic of this part. Assuming it is something that can go bad, it is either this that needs to be replaced and/or there WAS a loose connection and it drew down on the battery enough that it killed it beyond being able to recharge it. So hopefully it is either this power block of some sort, the battery, or both.

[mvusse]

I'd replace the battery first. One of the trucks at work we spent 2 years tracking down a non existent short before we found out the battery had a shorted cell and was draining itself.

 

Or at least take the battery out of the truck, fully charge it, let it sit for a few days and have it tested.