I have a 1980 W150 Power Wagon with 360/727. I've had the truck for over 4 yrs now and have had to replace the starter relay multiple times. I will lose all ignition and lights. Install a new relay and back on the road again.

Are relays made terribly crappy and this is a normal failure rate or do I have something more serious happening with my truck that is causing the relay failures?

Multiple starter relays over 4 years is not good, how are the battery cables?, new?, undersized?, do you have an ignition/fuel issue that is causing prolonged engine cranking to start?

You're not losing all ignition and lights through the relay, but those things will have ammeter and wiring issues at bulkhead etc.

Amp meters are junk in them.had probally 6 or 7 and every one had a burnt amp meter.I just put the wires together and installed a volt meter.Also as said check the battery cables.they might look good but many times they corrode inside.Rocky

It never happens while it's running/driving. I turn it off. Go to start it and no inside light, no headlights, horn. When I turn the key... nothing.

Cables are good. HD for a big truck. No starting issues. I always check cables etc and nothing... replace the relay and all is well again....?

Because you move the wiring around when you replace the relay. Next time just try moving the wiring at the bulkhead connector. Power to inside comes from the fusible link which is connected to the battery post on the relay and in through the bulkhead. The power doesn't go through the relay. You should take the bulkhead connector apart and look for a burnt terminal. If the relay goes out all that will happen is the starter won't work. Lights and everything else will work fine. As said earlier check the terminals on the amp gauge. If they get loose you will also lose all interior power. Loose wires there cause the amp gauge to burn out.

A bad relay does not cause the problems you are describing. Read this article on the shortcomings of the stock system and how to correct them.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml

as said there is a loose connection somewhere from the battery positive post to the bulkhead & you are jostling it when you R&R the relay which restores continuity! (for awhile). what I would do is turn the ign on & the radio up & under the hood start grabbing/shaking wires in that path. when the radio goes dead you've found it!

I had weird electrical stuff happening at one point too. Pulling apart, meticulously cleaning, opening up the connectors for a tighter fit, dielectric grease and reassembly of the bulkhead was one of the best things I've done for my car.

You're right. It's not the relay. I was able to get it to start once moving wires around. But after I shut it off.... NOTHING again. I moved wires. Tried to clean as many connections as I can but still nothing.

I will take apart instrument panel and see if the Amp Gauge melted or whatever.

IF it has, what is my course of action? Can I bypass the gauge and connect the two wires together and have it start or will it need to go thru the circuit board thru the amp gauge?

I can open the door to watch the dome light to see if I get connectivity. Despite moving, cleaning, reconnecting I still have nothing. It's a shame there's not reproduction/restoration parts for these trucks!!

its dead in the water right now correct? with your meter stick it in the bulkhead terminal where the fusible link is & see if it is hot. then we can work back toward the battery or thru the bulkhead to the ammeter. one of the 2 main wires on the ammeter might be loose or badly corroded.

Pretty sure the feed for the fuse panel and ignition switch ties into the battery cable at the starter relay. I don't have a 1980 FSM, but I do have access to a 79 wiring diagram so using that.

Which means that is probably where the problem is, not the ammeter. So rather than pull the dash apart look closer at the wires hooking up to the relay and there should be a dark blue wire hooked to the batt terminal, that's the feed. That wire has a fusible link in it. I would guess your problem lies there rather than the ammeter based on the wiggling "fixing" it then it going away.

Almost forgot, once I did see really weird symptoms with a fusible link. They're supposed to be good or burnt out, one or the other. This one was in between. I've only seen a fusible link do it the once. I don't know if it was bad connections on the fusible link or if it only burnt up part way but it gave symptoms like you say. I replaced it and all was good. This was on my sig car a few months after I got it.

roe

EDIT: I think it was partilly burnt because I remember it being soft like a burnt up fusible link is supposed to be. But this was about 8 years ago now

I agree its not the starter relay. The main hot feed does come off the starter relay at the large nut as that wire has an eyelet terminal on it and then should have a fuse link in it and it may take a few feeds from that wire at a splice in the harness as that should be a shunt type ammeter. It has to be in the wiring somewhere in that area where you touch and move the harness when you replace the relay. I agree that when it does it I would first go right to the hot feed at the firewall bulkhead and see if its got power there when it acts up and trace it from there by if it has power there or not. Ron

Have you looked at the connections in the bulkhead yet? There are terminals between the halves that can go bad. They will be obvious when you separate the connector.

After checking continuity to the bulkhead and finding everything in working order I moved inside the cab. I took the instrument panel bezel off and when I wiggled the hot wire to the Alt Gauge I would get power. So... I loosened, moved wire some, then re tightened. Power stayed on.

BUT.... now I have the same issue I had a couple weeks ago. I replaced the ballast and it was resolved. It starts then dies when I let off the key. It wasn't doing that prior to losing power. The Ballast tests good with .8 ohm resistance. Maybe I upset something moving/cleaning all the wires under the hood...?

Sounds to me like you have some issues with wiring. Check the wires ate the ignition switch, you probably banged into it when under the dash.

I disconnected and re connected the ign switch wiring. Made sure all wires under dash and in engine compartment were all seated good. It stays running with jumper to coil from battery.

What Supercuda said, there is another loose/corroded connection somewhere. with the key "on" the ign 1 "run" blue wire circuit needs to feed (1)the upstream side of the ballast and (2) the blue/yellow wire on the ECU pentastar connector (4 terminal ECU/2 terminal "single" ballast system I am assuming), since you only mentioned one ohm reading for the ballast. I would not jump the coil directly, that will burn out the coil and or the ECU eventually, we know the hard components are good, they ain't being fed, we (still) have a wiring problem

Ok.... FINALLY found the culprit. A wire going from the dash to the bulkhead was slightly loose. Re-seated and fired right up and stayed running.... Wooo Hoooooo !!!!!!!

Thanx to all!