horn issue and battery charging

A couple of questions from a novice.

Between the weather and schedule i haven't been able to dink around in my new truck much but thought i'd ask for some advice. My horn is barely audible, generally i think that means that power is getting to it and that the horn is toast (if it were dead it could be power isn't getting to it too, hopefully that isn't an issue with a moderately working horn). Would there be two (a high and low)? If one fails does that affect the other? any fast ways to diagnose it?

Also, i have a trailer special. I'm guessing the charging system charges both batteries? I don't have a schematic for the extra battery stuff. Anything special i need to do to make sure its working and stays working?

Also, a couple of moments on bumpy roads has almost made it sound like sloshing water somewhere. The interior is dry but I'm wondering where water drains when/if it gets in between the inner and outer cab wall. Such as water between the inner/outer roof cavity or in the rear cab wall if the rear window leaks. I know water is getting in somehow as there is a lot of rust visible on the interior side of the exterior roof that i saw when i removed the dome light.

Also, would this truck have any noises/buzzers for seat belts, lights left on, etc? I have a dash light for seat belts (works) but i thought there were some buzzers too...?

Thanks - Christopher

A couple of questions?    Anyway, I'll see what I can do.

The auxiliary battery system is shown in the 1985 EVTM here: Electrical/EVTM/1985 EVTM/Charge & Power Distribution (Gas).  You can see the relay depicted on the left side of the firewall on Page 14.  And it is shown electrically on pages 15 and 20.  But you should check that the aux battery is getting charged by placing a voltmeter on it when the engine is running, and you should see about 14 volts - the same as the primary battery.

On the horn, they grow weak.  One horn was standard and a second was an option.  They seem to get water in them and bleat rather than blare.  I'm not sure how to fix them, although I did fix one by running it full of contact cleaner spray and then letting it drain out.  And I fixed another by dropping it, accidentally of course.  It hadn't been working but did afterward.

But I don't have any experience with water inside the truck, so will leave that to someone else to answer.

The cowl drains on these trucks are very prone to clogging. Leaves get in through the slots in the cowl. get washed down into the drain pocket and block the small rubber drain valves. Best solution, once you have the drains clean is to cut a piece of plastic screen that will cover the area under the cowl grille and place it between the grille and body and that will keep the leaves out.

To clean out the drains can be a royal PITA, but if you take the rear attachments for the fenders and the one rear inner fender to firewall bracket bolt out, the bottom of the fender can be carefully pulled out to the point you can remove the rubber valve clean out the decomposed vegetation and reinstall the valve.

awesome, thanks to both of you!

Door also have drains, they are slots. 1 in each corner and 1 in the center.
If you hard water moving and it was water in the doors you hear it went the doors were open & closed.

Don't over look the drain for the AC and don't say "but I have not had the AC on because it's been cold & rainy. If you had the defrost on the AC runs.
Dave ----

well i had a fun day at the junk yard. Found some horns, an 8 track am/fm stereo, and a dome light with less corrosion. The horns sound great, the dome light has less pot metal corrosion but upon closer inspection the plastic lens and parts are in worse shape and everything is riveted together so i can't just swap out the parts i like from each set. Im saving the radio swap for a another day.

Also repaired the broken hood light wire but the light still doesn't work. What prompts the hood light to come on? headlight switch? does it only activate when the hood is up??

To see if your system is charging as it should, all you need is a voltmeter. Red and black leads right to the battery, set on direct current on your meter.With teh engine running around 1500-2000 rpms, you should be at least 13.8 and no more than about 14.3 volts. To make sure it can handle a load, start turning on tings. Headlights, fan blower are the two main ones that draw. Check the voltage again with them on. Shouldn't see more than 1 volt loss ( text book answer ). But really,  no loss or even just a couple tenths of a Volt less.

found the hood lamp wiring schematic/drawing. Is the mercury switch inside the plastic body? I must have a power issue somewhere that ill have to track down. I also took out the second battery to get to the horns. the truck is so new to me still that it wasn't until today that i noticed the second battery wasn't even connected!! Someone had disconnected it and tucked the cables out of the way for some reason (and here i was wondering why i had two starter solenoids).

Feels like i didn't get much done today but boy those horns sure sound good!

Horns, plural.    Glad you got them and got them working.

As for the battery, it'll charge better if connected.  

Sometimes it isn't the magnitude of what you get done, but the fact that you've peeled one more layer of the onion.  

EDIT: Forgot.  Yes, the mercury switch is inside the light's housing.

Ford had a TSB update on the mercury switch on a switch because the switch became unavailable. The switch update can be found here: http://www.supermotors.net/registry/media/71664

delco1946 wrote

I don't have a schematic for the extra battery stuff.

This is another way of looking at the aux.batt.:

delco1946 wrote

Also, would this truck have any noises/buzzers for seat belts, lights left on, etc?

It might, but that was optional.  It would be above the glovebox.  I don't remember if the box has to be removed from the dash to access it, but it just twists into an oval hole in the dash frame, and there's a ~3~5-wire connector on it.  If the truck doesn't have it, that connector is tucked into the plastic wiring channel above the glove box, and it can be pulled down & plugged into a JY buzzer.  I think it would be the white or green one in this pic:

delco1946 wrote

...a dome light with less corrosion.

The later plastic dome is a direct replacement, and its lens is better.  For a pickup with a tilted mounting surface, the flood lens (groovy) is better.  The spot lens is aimed for lights mounted horizontally.

delco1946 wrote

...the plastic lens and parts are in worse shape and everything is riveted together...

The lens comes off easily, but even a new one is still dim & foggy.

delco1946 wrote

What prompts the hood light to come on?

A tilt switch inside the lamp housing.  Which style does your truck have?





This caption describes the cowl drains:



This & the NEXT several show how to keep leaves out of the cowl:



There's also a drain plug behind the door that can be removed temporarily to release trapped water.  On later trucks, the factory foamed them shut, which annoys me...



But a more-common source of the water noise is low coolant, causing an air pocket in the heater core.  Disconnect either heater hose at the firewall, hold it about level with the nipple, and top it up until coolant starts running out the heater core nipple.  Then quickly reconnect them before much air gets back in.

These pics are very helpful! I think ill dismantle my underhood lamp (the ITT style) at some point to address the switch (after first checking the wiring to the switch/lamp, which may be the problem - haven't checked yet). I know i have some leaves and debris in crevices in the engine bay so I'm sure i have them in other areas too! I'll tackle this in the coming weeks.

I guess i was complaining about the larger dome light with the two angled spot lights rather than the more simple single style. I'll keep my eyes peeled when i go back to the junkyards!

I added a pic of the dome lamps.

I've got the chrome ones on the right. Although they use different center bulbs too.....

...And on my drive home tonight my drivers side headlamp started dimming. its always something!