Hooray my first electical problem 71 521

[pwrcat4000]

This Sunday I was at my nephews house, to yet again bleed the brakes. I hit the horn to let him know I was there... nothing. I  had him come out and push the horn all it did was click on the most forward relay? circuit breaker??? ( cant remember what its called) next  I un-pluged the wires on the  relay

one at a time

I then plugged them back in one at a time.  There is corrosion on all of them as expected.  I must have made a connection as the horn began working.  I bled the brakes ad went on my merry way

Next day, Monday,  I noticed, that none of my idiot lights are working , nor are my gauges. I was was needing to use my truck.  I know I have gas and my temperature  gauge never goes past half way, so I did not worry about it.

Tues still broke (lazy)

Wednesday, I was out late with the truck. Went to start it and it barely started. I turned on the lights, they were dim. I drove back to home base about 10 blocks I had no lights at all by the time i got home. I  figured it was a fuse or something not making good contact.  I fiddled around in the dark with the fuse block and burned the shit out of my finger. I shut off the 521 and just took the daily driver.

 

Today, went out had to jump the truck. When it is being jumped the horn works the gauges don't work at all, nor do the idiot lights.

I am afraid to figure out the connection that burned my finger last night .

What have i jacked up now ?

Some one had sent me a diagram a while back for the 1971 521 but I cant seem to find it.

[datzenmike]

Your battery is dead.

Your also not charging.

 

Clean your battery terminals and the cables. Tighten them securely in place.

 

Not charging may be the reason the battery is dead so have it charged. An easy way is to jumper to a running vehicle for 20 min.

 

Clean, check or replace your fuses. The one that burned you got hot because it was not making good contact. ANY resistance will get hot. Clean the fuse clips that grip the fuse also.

 

Now... is it charging? Is the charge light on? Gauges working? 

[banzai510(hainz)]

dim driving home means the altenator is not charging.

 

The Innova 3721 plug in to cig lighter works great(look it up)

 

Get one so you can see this coming before you drive too far

[MikeRL411]

Well, for the punctuation nazis, at least he used two punctuation marks!  The rest was a run-on jumble!  What ever happened to sixth grade English?

[DanielC]

Here is a 521 wiring diagram.

 

Never trust a glass tube fuse.  They can look good, and be bad.  If a fuse has been hot, there is a real good chance the fuse is bad, because the fuse element inside the fuse is just soldered to the end caps of the fuse.

A 521 instrument panel has its own fuse, that only get power when the key is on. the instrument panel needs power for the gauges to work, and for both idiot lights to work. 

There is also a wire that is hot only when the key is on, that goes to the voltage regulator, I think is is a white wire, with a light blue stripe.  This wire supplies power to the field coil of the stock externally regulated alternator, and that makes the alternator charge the battery.

[banzai510(hainz)]

get this or a version of this. Gives you and us a better indication of whats happening

 

http://www.amazon.com/INNOVA-3721-Battery-Charging-Monitor/dp/B000EVWDU0

 

most 521 proplems is corrosion at the fuse box. broken fuse or at the connections.

521 wiring is pretty basic. so do one thing at a time

 

 

most like the alternaot is just worn but have it cked and or reseat the T connector and secure the + and - at the alt.

[pwrcat4000]

Battery is topped off. 

Of course the truck will start and run.

I am sure it is not charging.  I have not diagnosed that problem, but, that should be a easy fix.   I will either replace the 521 alternator with a re-man or mod the harness to use the 620's. 

My concern is that when I was getting the horn to honk, again, I was working in that same area (right side of the engine room) as the external regulator.  Could it be the Regulator?  Looking at the wiring diagram seems like the power to the gauges and pod is coming from there. 

My spider sense is that it is a ground problem.  Ground problems are common on second gen trans ams though so that may be why.

 

MikeRL411

I corrected the original post for grammar.  I don't know if it was a low keyboard battery, or I voice to texeted it on my phone, but you were correct that was pretty bad. 

[banzai510(hainz)]

Why dont you get a volt meter and ck before posting if its charging.

clean connections first

[datzenmike]

Battery is topped off. 

Of course the truck will start and run.

I am sure it is not charging.  I have not diagnosed that problem, but, that should be a easy fix.   I will either replace the 521 alternator with a re-man or mod the harness to use the 620's. 

My concern is that when I was getting the horn to honk, again, I was working in that same area (right side of the engine room) as the external regulator.  Could it be the Regulator?  Looking at the wiring diagram seems like the power to the gauges and pod is coming from there. 

 

 

 

Trouble shoot the problem. Eliminate the things that work from the things that don't. Replacing electrical components that are working is expensive and a waste of time, not to mention the working parts are usually a better quality that the cheap rebuilt shit you find in stores. In addition you may install a bad new part, adding to the problem.

 

 Fuse box. Clean and fuses good? They should not get HOT!!!!!!!! Which fuse got hot????

[pwrcat4000]

Everything else seems to work except charging and the gauge pod.

The head light fuse, I believe, it was the hot one. 

I am going to remove the fuse block and really clean it up tonight.  Toothbrush and baking soda and water???

I also have an old school battery tester.

Not unlike this one. I am going to use it to check the alternator. 

 

I cant shake the feeling that it is something to do with the external regulator.

Is there an easy way to test it?

I have a multimeter but, I am not adept at using it, at all.

[banzai510(hainz)]

WHAT!!!!!!!!!!!!!!!

that photo is a battery load tester. Its NOT going to ck the alternator

Your lights working has nothing to do with the charging side as its running staright off the battery till the battery is dead.

You need to charge the battery via tha alternator.

 

2 ways to ck this.

Strart the truck and see whats its doing with the volt meter. with all lights off. then put lights on and then ck the meter again see what it says.

 

your volt reg cut the alternator voltage down from a unregulater hight voltage to say about 14.1 volts clean stariaght voltage. Most times these dont go bad but they will. But usually youll see till a hight voltage on the volt meter. showing that the alternaotr still works.

 

You could pull the alt off and take it in .

 

PS buy a solid state volt reg from autozone or carquest and they are better than the NAPA mechnaical type as they dont last long at all.

 

 

I had no charging once on my 521 and it was the instrumentpanel poping the ignition fuse. I reseatting the panel connector then everything was good.

[pwrcat4000]

Banzi,

Thanks for the advice but it can also be used to check for charging (that is just a picture off the Internet).

If you look closely at the meter it tests the charging system too. You just leave it connected after starting.  I have done it many many times.

"Determines state of charge, cranking and charging volts"

 

Wait, I had to install a momentary switch, as the key switch failed to start the truck, but that was weeks ago.  I followed instructions

here

http://community.ratsun.net/topic/56464-just-bought-a-1971-521-for-5-large-500/?p=1365892

[pwrcat4000]

This wire was not making good contact

(FYI there is another wire that I removed just to take the picture)

 

 

After cleaning the terminal and connector and reconnecting this is the reading while running.

 

 

The battery read 12.5 volts with the ignition off.

 

I am guessing since the battery was fully charged that the charging voltage does not need to be 14 volts? 

I know my T/A, that has a volt meter gauge, reads lower if the battery is up and charged.

What do you all think?

[HOGIE]

Based on the wire diagram that Daniel posted up that wire goes back to the voltage regulator, so you were sort of right

[banzai510(hainz)]

13.5 at idle is maybe OK

try rev up motor and maybe you get more. with no lights/heater on.

 

I notice on my 521 I let is warm up(cahrge battery) first before I put my accessories ON. It helps.

Stock 35 amp alt one should monitor with the Cig lighter battery/alt checker. Its does work.

 

 

try load the batter and ck the voltage with lights on and rev motor.

 

I had a 280z that during the day cr was fine. At night drive home next day the battery was low or dead. Find out my batter was draining at night by having heater and lights on. Daytime was fine cause I wasnt loading the system.

Alternator was weak

[pwrcat4000]

Stock 35 amp alt one should monitor with the Cig lighter battery/alt checker. Its does work.

I will probably get one of those. Longterm, I think I am going to build, or find, a gauge cluster for it. 

I hate not having oil pressure volts and tachometer <----- car nerd.