rabbithutch

I posted some of this under a post about the serpentine belt. I thought the belt was bad but I got an opinion from a more experienced friend who said he thought the belt was ok because there is no brittleness or fraying and the grooves are not worn down.

So now I'm thinking there is something wrong in the ignition system. When trying to start with the key, the starter relay clicks once each time the switch is turned to start. I only recently learned of the post to post shorting maneuver to see if it would start. I haven't tried that.

Before posting more, I need to get some terminology straight in my head. I've always called the fender-mounted switch behind the battery with its 4 main terminals and a starter post a 'relay.' I've seen YouTubes and articles that call it a solenoid. I thought the solenoid was the unit mounted atop the starter. If I'm wrong, please straighten me out.

I have put a multi-meter on the battery and got a 12.46 VDC reading which I read somewhere was too low. Before putting a charger on it. I removed the wires from the starter relay switch (see para above) and cleaned and inspected all the wires to be sure I had good connections. I have not checked wiring to starter and alternator because I'm an old man (75) with spinal disk problems and arthritis and can't crawl in and under like I used to.

After reattaching the cables to the relay switch, I connected a charger to the battery with a 6 amp charge rate and let it run for several hours. Afterwards, checking with the multi-meter, I got less than 6 volts. I must have overcharged the battery and probably destroyed it. My charger does not have a limiter on it and I got busy doing something els and didn't pay attention to the charger readings.

Now, the relay will click once despite the charge on the battery being low. Because the battery seemed to be just a bit under charge when I started diagnosing and because the truck isn't driven daily and only about a 1k miles per year, I thought the battery was probably OK before I tried to charge it. Before I pop for a new battery - and maybe damage it - I thought it prudent to ask the experts here what else I should check before doing so. Also, where do I go to get the right spec for a replacement battery wrt amp hours, starting load, etc.

Thanks in advance for any advice.

BLDTruth

It is a group 65 battery....I am a big fan of interstate batteries.

The fender relay/solenoid is only there to give power to the starter when the key is put into the on/run position. Without it the starter can drain your battery. Put the key in, turn to run position, make sure the truck is in park or neutral, and cross the posts on the relay. If it starts, that means the fender relay is bad. If it does not start, measure voltage to the tiny wire that has its own special post on the top of the relay. If it has no voltage, it is a problem with the wiring or ignition switch.

12.46v for a battery is great. 14.4-ish is what you want while running. If it is less than 14, your alternator.is not charging properly.

Steve83

The ignition system is what fires the spark plugs - the system that spins the starter is the "cranking" or "starting" system. Your problem sounds like bad battery terminals. Click these & read all the captions:


(phone app link)

The device by the battery is the starter RELAY, and yes - it's commonly referred to as a "solenoid", even though it's not. Your truck doesn't have a starter solenoid (which is on the starter) - that change happened in '92.


(phone app link)


(phone app link)

It's not likely that you bricked the battery by charging it for a few hours - more likely you didn't get an accurate reading with your meter. Are the meter batteries good? Did you check at shiny-clean metal surfaces? Did you check between the battery POSTS (not the clamps AROUND the posts)?

rabbithutch

Howdy, Steve! Thanks for the response. I like your signature.

My battery cables and posts are in good condition. I cleaned the terminals when I removed the battery cables. I use those little treated circular pads under the cables to fight oxidation. There is none and the cable ends are in good condition. I also cleaned them. All connections are tight. I checked the battery on the terminal posts. The multi-meter could possibly be the problem, but I don't think so because I've used it withing the last few days to check small battery voltage, AC voltage (to the charger) and voltages on a computer power supply unit and got readings expected. I will check it's batteries, though. That is something I haven't done.

I'm working from the assumption that the starting relay is OK because it clicks when the ignition switch is engaged to try to crank the engine. It only clicks once, but I've read that if it clicks at all it's OK.

Wiring is obviously old, but the terminals seem to be firmly gripped and there is no visible damage or corrosion. I will check continuity in wiring as I go. Both battery cables checked OK. I'll check ignition coil wiring and starter and alternator cables when I can get under the vehicle.

Thanks for the battery info, BLDTruth. When the rain stops in a few days, I'll give everything another check, especially shorting the relay posts, if the battery checks OK. I, too, am partial to Interstate batteries. I'll start shopping for a group 65.

I've read that the ignition switch or its wiring or the ignition coil and it's wire could be bad. I haven't found any description of how to check those components, yet; so and tips would be appreciated.

Steve83

A relay (any relay) can click & still be bad. When it clicks, the voltage across its load terminals (the big studs, in this case) should instantly equalize (to ~12V in this case) regardless of the size of the load (the high-current starter, in this case). If the voltage is not equal, the relay's internal contacts are bad, even though they're moving mechanically (the click). That's an especially-common problem on early-style starter relays because tightening them causes their contacts to misalign internally:


(phone app link)

If yours fails that voltage check, replace it with the newer design:


(phone app link)

The ignition & alternator wiring are on top - no need to get under for those. But neither is involved in cranking, so there's no point worrying about them until you get the cranking system working again.

This describes a known problem with that type of ignition switch, and the caption contains a link that explains how it should work, and how to test it:


(phone app link)

IF you find the battery needs replacement (now or in the future), I highly recommend MotorCraft TestedTough Max BXT-65-850. This caption contains a link to Ford coupons & special offers:


(phone app link)

But the only way to actually test the battery is with this brand & type of meter:


(phone app link)

BLDTruth

Agree with Steve - clicking means nothing. Measure the voltage.

rabbithutch

Got off the honey-do list long enough this past weekend to try a few more things.

First, I checked voltage - again - in the f150 battery. It showed 7.6VDC. I guess I bricked it when I put the charger on it. My charger does NOT have a charge limiter and I didn't pay close attention to it while I was working on other things.

Because the battery checked bad, I took it out of the truck. I then checked voltage on the battery in my wife's Honda and got 13.89VDC. I then used jumper cables from the Honda battery to the battery cables on the f150. After connecting, I checked voltage at the truck battery cables and got the same 13.89VDC.

I then tried to crank the truck and got the single click from the relay. I left the switch in the 'run' position and checked voltage between the 2 primary posts on the cranking relay. I got the same 13.89VDC. I then tried to short the cranking relay while the jumpers were connected to the battery cables on the f150 and the Honda which was running at idle. I got nothing. No sparks, no cranking . . . nothing.

Now I'm confused about symptoms. Obviously the battery must be replaced. Do the cranking relay test results indicate that it, too, needs to be replaced?

The truck is just an extra vehicle for me to beat around in, I haven't pushed hard to get it running again. In fact, I took the battery tray out to clean and repaint. There was right much rust and pitting, but he metal is still solid. I got all the loose rust off and plan to put it in an electrolysis bath to get rid of the rest before I paint it.

I'm still open to, and grateful for, any and all information and suggestions.

Thanks again,
rh

Steve83

Without seeing (or a better description of) what you did to the starter relay, it's hard to diagnose. But no, I wouldn't replace any parts until you KNOW they're bad. It's unlikely that 2 critical parts failed simultaneously, and you already assume the battery did. So the relay shouldn't have (unless you did something to it during the battery shenanigans). But I'm still not convinced the battery is ruined. Try connecting it by jumper cables to the Honda, and letting it idle for an hour. Clean all the connection points, and DON'T reverse the polarity. Check its voltage before connecting, immediately after connecting, and every ~15 minutes during jump-charging. If it drops below 12.5, raise the Honda's idle; if it drops below 12 or rises above 14.7, disconnect everything.

rabbithutch

Thanks yet again, Steve!

We're having showers today and I have not means to get the Honda and battery under cover; but I will give your suggerstion a try when the rains stop.

rabbithutch

Sorry to be so late with the follow up, but I finally remembered that the thread was hanging, so to speak.

The problem turned out to be only a bad battery. I cannot understand why my early checks of voltage on the old battery showed that it was within the reasonable range but was the fault all along. I haven't made the time to take it by to have the alternator checked but will do that just to be sure the battery is charging. I don't really trust the instrument cluster ammeter.

Thanks again to all who responded with suggestions.
rh