Weigle

Like a dumbass, I didn't disconnect the negative battery cable when I starting to wire up my mini-SR5 gauges. STEP 1 in most instructions. . . "disconnect negative battery terminal."

I had the non-SR5 instrument cluster out trying to splice into the wires behind it and while I was under the dash two wires connected, sparked, then the rubber sheath around the two wires disintegrated in a poof of smoke.

As a result, when I turn the ignition on the CHARGE and BRAKE light are lit. I searched for an answer for 2 days before posting, and didn't find anyone with a problem quite like mine. . . The ENGINE fuse blows each time I turn the truck on now. The wire colors running to ENGINE fuse are BY and R.

Here are some facts that I didn't have (all) in common with other posts

TRUCK SPECS: 1982, Original or old-looking IC regulator, 40A Beck Arnley Alternator, de-smogged

• The CHARGE and BRAKE light are always lit when the ignition is turned on.
• Revving the engine under no-load will not make them go out
• Driving the car and getting up to about 10mph WILL make both lights go out
• The truck idles like crap and won't choke (awaiting reply to manual choke post: Which can be read here
• The 15A ENGINE fuse blows every time I replace it
• I checked the CHARGE LAMP RELAY and it appears to be ok. Tapping on it has no effect, removed for visually inspection.
• The battery has 12.5V at rest and is only 1 month old
• While the engine rev's under no load the battery remains at 12.5/12.4 V
• When I run 10mph'ish the volts will suddenly jump up to 14.xx and remain there, then the choke will start to work.
• After the truck is warmed up, the battery will remain at 14.xx volts even at idle until the truck is turned off. If I immediately turn the ignition back on, the CHARGE and BRAKE lights are lit again and the battery reads 12.5V until I drive 10 mph or faster and it will jump to 14.xx V
• The drive belt is nice and tight
• I opened most all of the green connectors and checked ground wires, and most wires not wrapped up and did not see any signs of failure.
• When the wires I was working with shorted, there was a power wire spliced into the radio. I found out today the "power" for the radio was jumped between two different fuses by the previous owner which were the RL and WHITE wires pictured below. They are the 15A TAIL and 15A HAZ-HORN fuses.
• My speedometer cable is not connected at the moment, could that be a possible cause for this entire fiasco since it wont begin charge until I actually MOVE, regardless of RPM's - but remember, it will charge at idle once that initial "umph" down the road happens.

Strange huh? Better pull out those FSM's and start unfolding the diagrams in the back

By sticking a wire connector between the W and RL wires, the previous owner basically bridged power the STOP, TAIL, and HAZ-HORN fuses to supply power to the radio instead of just using the RADIO fuse slot ARE YOU SERIOUS?! Yes.

Today, I spliced the radio power and gauge power into the appropriate fuse banks but now I'm left holding a "charging system nightmare" membership card.


When this occured, I had about 5 wires hanging down at the time so I'm not 100% sure which two wires accidentally crossed but I am 100% sure I'll be disconnecting my negative terminal when working on the truck from now on.


So, what is my next step? I can't think of anything else to test unless I start replacing parts. The Napa Bosch rebuilt alternator comes with external regulator and every other part I need for about $70. They have cheaper rebuilt alternators that also include the external regulator as low as $30 which I'm suspicious of.

Lastly, there is a "green plug" option - any info on that? I'm not ready to switch to a GM 1-wire unless it's the same cost as a $70 alternator. I'll need to run a winch in the near future though.

sigh. . .

Thanks guys!

peow130

GM 1 wire is going to pay for itself once you get that winch. You can make the brackets yourself using some 3/16th strap steel

Weigle

Yeah, probably so. . . it's my daily driver and there isn't usually a day when I don't need to drive it so I need a quick fix until I can read some posts on the 1-wire swap unless someone has part numbers and instructions handy. Tutorials are usually easy to find, part numbers for everything tend to take a few extra searches. I've seen a few tutorials, but most seem to be for 22-RE and newer trucks/4Runners 84-95 and not for 79-83 trucks and a 22R. I'm a big boy though, I'm sure I can find one!

For now, do you think it will harm anything to drive it? Could the diodes in the alternator be bad and allow the alternator amperage (40A) backwards into the 15A ENGINE fuse; therefore, blowing it every time the ignition is on?

cableguy02

the one wire swap takes an hour tops.. and will save u money in the long run.. trust me lol search trail gear and order the brackets if u dnt wanna spend the time building the backets. mount up the gm alt and hook the heavy white whire up to the alt.. done

suncomb1

The 15A engine fuse connects to the ignition switch, voltage regulator, choke heater, and emission components. If the engine fuse blows all of the time and the engine runs rough then I would check the emission components-cold mixture relay, VSV's, ECU, etc. If one of these is shorted to ground the engine fuse will blow instantly. Replacing the alternator with a GM 1 wire most likely will not solve your problem if any of the above are damaged. Because you say the engine will not run smooth I would check the ECU first. Good luck.

Weigle

Problem solved! I can't explain "why" it works, but it fixed my problem. I stated that the PO had wired the radio power by jumping those two fuses, which I also unknowingly connected the gauges to as well by splicing into the radio wire.

To fix it I placed the wires in their appropriate location by:

1. Connecting the radio power to the original LB radio wire at the fuse box
2. Connecting the power to the SR5 mini-gauges to the Y wire at the fuse box
3. Replaced the 15A ENGINE fuse once again after correcting the connections

Now, everything works perfect. . . except the aftermarket radio now loses power when the ignition is off; therefore, I lose my pre-sets. Maybe I need to connect to the LR radio wire instead of the smaller LB wire. I'm going to buy a new radio anyway so at this point, I'm just happy my truck works like it should!

Thanks guys! You all are awesome, and for anyone teetering on buying a REAL FSM - TOTALLY WORTH IT. The other "auto parts store" manuals don't even come close to the FSM

Weigle

Scratch that... After a full day of normal operation the same problem is back! I hopped in the truck after stopping briefly, turned the key, started the engine... CHARGE and BRAKE are back on, then go away after nearing the top RPM of 1st gear but runs bad at idle.

Before I had turned the engine off, I noticed one of my fresh dash lights was blown that illuminates the temp gauge. I didn't think much of it, except that it reminded me when the dead ground happened there was a wire connected to the tail light relay as well. I think it was on the RB wire. I can't say for certain if that wire was involved in my charging system's downward spiral though.

Suncomb, the truck has been de-smogged so there are no emission components to check.

Any ideas?

Weigle

So here's the latest. . . I tested the Charge Light Relay by connecting it to the battery as instructed in the FSM and there was an intense spark show when I hit the negative terminal. I double checked my connections they were correct, so I did it again but this time there were less sparks. On the third and fourth time there were no sparks at all.

I also tested the IC Regulator by following the FSM and connecting a voltmeter to the red wire, and grounding it. The reading was .74V

Of course, the fuse blew before I even started the engine and the key was in the ACC position. Could my instrument cluster be bad? I think that's where the wires that dead-grounded were connected, and I know there was a power connection from the "radio" which was still connected to the STOP and HORN/HAZ fuse.

I think I'm going to rig a little 1W light up to the engine fuse and tape it to the steering wheel column so I can see exactly WHEN the fuse blows.

There is still the lingering issue of why the radio won't hold it's settings when the key is turned off OR why the truck starts to charge under load and not an increase in RPM. My temp gauge light on the dash burned out shortly after tapping the mini-gauges into the GAUGE fuse . . I feel like the issues are all related.

The mini-gauges are connected as follows:

12V - From gauge fuse (Y)
Ground - Cigarette lighter wire (BW)
Light 12V power - dash light above heater control (RW i think)
Light Ground - dash light above heater control (BW)

suncomb1

I still would check the emission system components for dead shorts especially the VSV solenoids. If you look at a FSM diagram that shows everything off of the ENGINE fuse the charging circuit and ECU emission control circuit is what is connected to it besides the ignition switch. Remove all add on wiring from the Engine fuse portion of the fuse block or taps first so the wiring circuits off of the engine fuse is as factory wired. Disconnect the ECU plug and Emission component wiring plugs and see if the fuse blows. If it does not, reconnect the ECU plug only and see if the fuse blows. If the fuse does not blow then reconnect each emission component device one at a time until the fuse blows. If after reconnecting all of the emission components and the fuse does not blow check the wiring in the charging circuit by disconnecting all components and check the wires in each circuit for grounding.

Weigle

I had my entire dash apart this past weekend looking for signs of trouble. I found the factory plug for the mini-gauges WAY back behind the radio so I removed my ghetto-splice connections and plugged directly into the OEM plug.

I checked just about everything I could visually and didn't see any signs of damage.

I noticed that the alternator will start working in neutral if the RPM is high enough. I'm guessing 3,000+. I don't have a tach but it's the same point each time just listening to the engine.

The charge light isn't coming on anymore but the voltmeter reads 12v until a certain RPM is reached then the alternator will come on and stay on, even at idle. I found some "interesting" connections near the drivers kick panel, around the ECU. I'm going to continue diagnosing but hope is fading and the GM 1-wire looks more attractive.

I don't have any emission components in my engine bay to check. It's clean and free. I'm about to search topics about unplugging the ECU since my engine is de-smogged. If that doesn't fix it, then I'm back to square 1. The fuse blow is so random. Sometimes it will blow when the key is simply turned to the ACC position and other times it blows randomly while driving. I cannot detect any pattern to it.

Thank you all for the advice. I'll continue working towards a solution.

suncomb1

If you have no emission components on the engine do you still have the fuel tank vent control and canisters. If you do, check the VSV valve. If you unplug the ECU you effect the operation of the fuel tank vent system. Is a condenser still mounted on you alternator? If it is check or replace it. Have you tried a temporary jumper wire from the battery to the red wire on the IC voltage regulator thus by passing the Engine fuse (REMOVE ENGINE FUSE FOR TEST)? Have you disconnected the charge light relay completely? Stupid question-Do you have an underdrive pulley system installed on your motor?

Weigle

No, only the fuel tank canister is installed. The carb canister is gone.

Negative.

I haven't. What conclusions can I assume by conducting this test? 12V (or not) on a voltmeter at the red wire is where I start I assume?

Yes, The charge/brake light do not illuminate any longer. I think I fried the relay when testing as instructed on page 8-18 of the FSM. See post above for "spark show" details regarding the charge relay.
Doubtful. . . the pulleys on the crank and alternator appear OEM but I don't have any diameters to compare them to.


I did locate "diode" under the dash as illustrated in Figure 2, section D7 of the FSM wiring diagram that definitely has an aftermarket "STANLEY" cap on it that appears to bridge the 2 Red/Red wires with the RW and B wires. I can't find any information in the FSM about this "diode."

Any thoughts on simply removing the ECU from the equation?

baddest94

Hey i got a similar prob with my batt and brake light in my truck they say on constantly never go off. They alt charges correctly and batt never dies a buddy who messes with toyota's all the time told me that it was the voltage regulator in the alt and as long as it was charging right and wasn't haven probs out of it it would be fine so i just put a pic of my ol lady and lil boy over them LOL. Don't have any of the other probs you are having. But he told all i needed to do would be change the alt. The lights don t bug me so i havn't messed with but if there is something else thats causes this id like to find out just in case when it quits charging and i replace the alt and it still stays on ill have somewhere to look. Ill be keeping an eye on this hope you get it figured out

wyoming9

iTrader: (1)

if you can`t find the short that keeps blowing the fuse just put a 50 amp fuse in so that when the wires start to burn you can find it.

using this method works but most often needs a fire suppression device or your local fire company.

Not a real good idea to do around the garage or house.

suncomb1

The purpose of running a 12V wire directly to the red wire on the IC regulatory, removing the Engine fuse and removing the Charge Light relay is that by doing so you have isolated the alternator circuit other then the diode. If you start the engine and check the voltage it should be normal if the alternator and IC regulator are okay. If you have a DC Amp meter you could measure the alternator Amp output. If the alternator does not output about 13.5+ volts then you have a problem with the unit. Your short or fuse blowing problem could be in the ignition switch itself. If you have a tilt steering column you could have damaged wires (they are famous for breaking wires). Pull the cover off and look at the wiring in the steering column area. If you remove the ECU, you should remove the fuel tank canister and install a small air filter on the vent hose so the fuel tank will vent properly.

warmonger88

Weigle, did you ever get htis sorted out? I'm having the same issue with my 84 22r. I stripped out the emissions system, except the ecu, have a weber carb and a manual choke. I had by alternator tested yesterday and it passed, replaced the voltage regulaor, had my batttery charged. I can't get it to charge the battery and the charge and brake lights on the dash won't turn off. I haven't blown any fuses yet though.

Weigle

In my instance the electric choke was shorting out against the housing. A manual choke installation solved my issue, and took a weak link out at the same time. I don't know much about an '84 but you'll enjoy running emission-free! Does the 84 have a charge light relay? Look in the real FSM...seems to be another common charge light issue.

warmonger88

my 84 isn't too different from the previous years, especially when it is emission free. I do have a charge light relay, I just need to find another one to give that a try. Unfortunately my parts truck had every relay but the one I need. Did you do the one wire upgrade too? If so did that help at all?

Weigle

I didn't go with the 1-wire upgrade. I wasn't ready to pull the trigger on that project just yet... Let us know what you find. I think I have two charge light relays if you need one PM for a price. You can test their functionality pretty easily to identify if that's the problem or not.

warmonger88

I appreciate that, but I'm gonna try the junkyard in town first. I have a few other things to pick up and the gal at the office cuts me deals if I buy a bunch of stuff at once.