No ignition / start / dash power after heater hose leak.

[sona1111]

Hey again guys, could use some help with an electrical problem. Sister was driving 89 LX carb AT yesterday and one of the heater hoses blew up. It was the 'P' shape one right above the alternator. I just finished replacing that and filling coolent, but now no lights come on in the dash in the run position and no crank in start position. (I guess, some of the leaking coolent dripped onto the Alt and shorted something) Also power windows will not move which is bad because they were left down. Cabin dome light does turn on. I checked both fuse boxes: the inside one was fine ; the under hood one had 3 blown fuses, 'BATTERY' (70A), 'LIGHT' (40A) and 'fog lamp'(15A). I replaced them all, (but currently the 70A BATTERY one only has a 60A fuse because the parts store did not have the correct one, will correct when I can). Replacing them did not fix the no-ignition / light/start issues. Any insight where I could check next? As a stopgap is there a way to override just for the windows so that I could roll them up?

Thanks for reading!

[Oldblueaccord]

Hey again guys, could use some help with an electrical problem. Sister was driving 89 LX carb AT yesterday and one of the heater hoses blew up. It was the 'P' shape one right above the alternator. I just finished replacing that and filling coolent, but now no lights come on in the dash in the run position and no crank in start position. (I guess, some of the leaking coolent dripped onto the Alt and shorted something) Also power windows will not move which is bad because they were left down. Cabin dome light does turn on. I checked both fuse boxes: the inside one was fine ; the under hood one had 3 blown fuses, 'BATTERY' (70A), 'LIGHT' (40A) and 'fog lamp'(15A). I replaced them all, (but currently the 70A BATTERY one only has a 60A fuse because the parts store did not have the correct one, will correct when I can). Replacing them did not fix the no-ignition / light/start issues. Any insight where I could check next? As a stopgap is there a way to override just for the windows so that I could roll them up?

Thanks for reading!

Does that underhood fuse box have power to it at all. It may have burnt the connection coming from the alternator.

Coulds use a jumper wire from the battrty to the fuse for the windows just to get them up. Just hold it while someone rolls them up.

I would also leave the battery unhooked until you get it straight ened out.

[sona1111]

Hi, Oldblueaccord. Thank you for the reply. It is still sitting in the parking lot over there for now, so I will go and try to check tomorrow. To make sure I understand:

-I can check for power to the fuse box under the hood by looking for no resistance between positive battery terminal and one side of the 'BATTERY' fuse?
-It seems like a likely culprit is a short (likely dispersed now) between the positive alternator cable and the body of the alternator, due to coolant falling all over it. If this short occurred, and the fuse reacted too slowly before blowing, the positive alternator cable may have been burnt and compromised. However, would this cause no power at all to dash/starter, or just an alternator that does not charge?
-In either case, I can check for no-resistance between positive battery terminal and positive alternator cable connection, and there should be none if the cable is good.
-To move windows up, ignition switch can be bypassed by connecting a wire from the positive battery terminal to one side of the power window fuse, and using the power window switches in the car.

If you happen to have a chance, please let me know if I am understanding you correctly.

Thanks and have an awesome day.

[Oldblueaccord]

12 volt test light would be a start.





better a real Digital multi meter.

ROBOT WARNING - at the Test Equipment Depot

I agree with all your point but I wouldnt worry about "resistance" test. Really you are looking for "continuity" bewtween points which with a meter is check with the POWER OFF. more important in AC systems esp at higher voltages like 480V. Blowing up a meter in your hand is never a good thing.

Since this is 12 volt DC its a little safer. You check for with POWER ON and look for the light to light up.

All the fuses blown does mean a short and yes possible wire damage someplace.

[sona1111]

Hi OldblueAccord, sorry to waste your time, it turned out to be something simple: it seems that somehow the screws which hold the fuses in were corroded, and after cleaning everything up things are working again. Will replace the 60A with 70A once it comes in.

[Oldblueaccord]

Good work!

No time wasted!

I usually respond while at work anyway......

[sona1111]

Slight update on this, though I don't think I really need a response. After a days commute the battery light has been coming on/off during the drive, so the leak also caused the alternator to be going bad it seems! Oh well, will replace that next...

[sona1111]

Hey Guys,

Weird update for this if anyone has ideas: when the coolant spilled on and ruined the alternator, I was getting about 12.4 volts at the battery while the car was running. I have just replaced the alternator and now I am getting a nice 13.7 or so volts at the battery while the car is running...but the battery light is still on. Is there any other subsystem that might have failed to make the battery light go on? Or maybe I just have to drive it for a long time to charge up a bit more for the light to go off?

Let me know if anything comes to mind, otherwise oh well.

[Oldblueaccord]

With a carb car there is something with the choke heater wire and the alt light. Search around for that.

[Dr_Snooz]

Check out p. 24-21 in the manual (https://www.dropbox.com/s/vzcxevmh7x...anual.pdf?dl=0).

[sona1111]

Hi Dr_Snooze,

Thank you for the pointer. I have ignored this for a few months because things seemed to be working relatively ok but now problems have arisen again.

First, the bigger problem: charging is not working well anymore. I get ~12.5 Volts at the battery at idle and ~13.5 Volts when revved to about 3krpm. This does not seem to be enough to keep the battery charged and when using accessories the car will likely die. The Alternator was re-manufactured so I am not ruling that out, I just want to be sure because I just replaced it only a couple months ago.

The charge warning light is still funky as well. When key turned to ON, the light does not come on. Following page 24-21 in the manual I took the white/blue wire and touched it to two different ground points and turned the key on again, and still no light. In this case the manual lists a whole slew of possible causes. I checked the fuse first with a meter and it was fine, and I really doubt the bulb is the issue because the light frequently has been coming on and off randomly while driving. Next it says to inspect wires from the bulb to the positive (blk/yel) or our ground point (blue/white) - does this involve removing the whole dash or is there some intermediate point to check? Could this fault cause the poor alternator output, or would that most likely be something else?

Appreciate your advice and support!

Thanks for reading.

[sona1111]

Slight update from tonight's work:

Both of the other wires on the alternator harness are correctly at battery voltage while key is on.

I also ran a second thick wire from the alternator positive post directly to the positive battery terminal, this made no difference.

I also tried some other experiment: with car on, disconnecting negative cable. In this case the car continues to run but the rpm dropped a bit. When I check voltage between negative cable (disconnected) and positive post with car on, I get the correct 14.4-14.6 volts, as soon as I connect the cable back to battery voltage drops down to 13 again (alternator can't keep up with load?) I can try yet another alternator if anyone thinks that would help, but I find it strange that I got low voltage on old and new alternator now...

Thanks for reading.

[Shane86]

If you seen the alternator light come on or flicker I would go ahead and replace it. Or have it tested at more than one place

[sona1111]

Ok, I tested with an additional ground cable connected as well, and no difference. Going to try a third alternator: has anyone had any luck with NAPA 'new' alternators? any good?

Thanks!

[Oldblueaccord]

Ok, I tested with an additional ground cable connected as well, and no difference. Going to try a third alternator: has anyone had any luck with NAPA 'new' alternators? any good?

Thanks!

Did you go thru the choke heater wire testing. This is related to the charging some how.

[sona1111]

Choke heater plug is not connected to anything - I have disabled it. I used another source for choke power a while ago (year at least)

[Oldblueaccord]

Choke heater plug is not connected to anything - I have disabled it. I used another source for choke power a while ago (year at least)

http://repairguide.autozone.com/znet...528005fa08.jpg

I think that has to be in the charging circuit to get it to charge.

[sona1111]

Hi Oldblueaccord,

The diagram you posted is very low resolution, I can not quite see it. It does not seem to make sense that the choke heater needs to be connected for the alternator to charge - it is just a single wire which I assume goes through the heater (resistor) and to ground. There is not any other logic in the circuit (?). Anyway I ended up replacing with a NAPA alternator and the voltage is good now. I guess the battery light is a separate issue.

Thanks for trying to help.

[AWH]

Hi Oldblueaccord,

The diagram you posted is very low resolution, I can not quite see it. It does not seem to make sense that the choke heater needs to be connected for the alternator to charge - it is just a single wire which I assume goes through the heater (resistor) and to ground. There is not any other logic in the circuit (?). Anyway I ended up replacing with a NAPA alternator and the voltage is good now. I guess the battery light is a separate issue.

Thanks for trying to help.

Have you actually read the link Snooz posted ? And tried the suggested steps to take ? If you read it you'll find it does have something to do with your batterylight.

Auke.

[Oldblueaccord]

Hi Oldblueaccord,

The diagram you posted is very low resolution, I can not quite see it. It does not seem to make sense that the choke heater needs to be connected for the alternator to charge - it is just a single wire which I assume goes through the heater (resistor) and to ground. There is not any other logic in the circuit (?). Anyway I ended up replacing with a NAPA alternator and the voltage is good now. I guess the battery light is a separate issue.

Thanks for trying to help.

its sensing voltage to regulate the alternator internally. Full field and alt can run up to 16 volts. They may use it because of resistance in the circuit.

Glad it is working.

Also remember car alternator charges LESS at idle then they do at high RPM. So a large amp load at idle may read low voltage on your meter. You may not get more than 25 amps at idle on a 70 amp alt.

EDIT:

Couple links to put you asleep.

Alternator Theory v15

https://en.wikipedia.org/wiki/Alternator_(automotive)