1997 F350 w/ the 7.3 (auto) 2wd. Last night it barely started--had to cycle the glow plugs 10-12 times before it fired. Temp was not cold--maybe 30'. Batteries are good. This seems to happen every 2-3 yrs and the fix is always a new GP relay. First time it happened was when I bought the truck (used) and I put in a Motorcraft relay--lasted 2 yrs. The last time I replaced it with a generic brand and got roughly the same life out of it. Looking for ideas why I'm going through them so fast (at least I feel they should last longer since we don't use the truck every day). And secondly, any recomendations on another brand of relay that may last longer? Also, I need to find it locally so mail order is out of the question--need to replace it my Monday.
If you have a shop in your area that sells snow plow parts check and see if they have a relay for a Western snow plow the part number is 56131K-1 some have been using them with good results. Other than that the best out there is the Stancor 586-902 but you will need to order it. If it was me and I couldn't find the Western one I would pick one up at NAPA, part number gpr109 for around $20.00 and then order the Stancor one.
The reason that they fail is that most of the relays are not designed for the amperage that the glow plugs draw. If you ever cut one apart you will see metal pitting on the contacts that will cause them to fail.
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96 F250 PS XLT 4X4 long box, 5sp,4.10, manual hubs,pyro+boost guages, Dark Toumaline, add a leaf, Dale's TYMAR, and HX hose, downpipe, coolant filter, Luk clutch
If you have a shop in your area that sells snow plow parts check and see if they have a relay for a Western snow plow the part number is 56131K-1 some have been using them with good results. Other than that the best out there is the Stancor 586-901 but you will need to order it. If it was me and I couldn't find the Western one I would pick one up at NAPA, part number gpr109 for around $20.00 and then order the Stancor one.
The reason that they fail is that most of the relays are not designed for the amperage that the glow plugs draw. If you ever cut one apart you will see metal pitting on the contacts that will cause them to fail.
Thanks, I'll se if I can source the Western one on Monday and order something better--or the Napa one.
Just so that you didn't miss understand me the NAPA gpr109 will work but it is no better than the factory one. I ran one for 6 months before I put the Stancor in and the 109 is in the tool box if I need a just in case spare.
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96 F250 PS XLT 4X4 long box, 5sp,4.10, manual hubs,pyro+boost guages, Dark Toumaline, add a leaf, Dale's TYMAR, and HX hose, downpipe, coolant filter, Luk clutch
Just so that you didn't miss understand me the NAPA gpr109 will work but it is no better than the factory one. I ran one for 6 months before I put the Stancor in and the 109 is in the tool box if I need a just in case spare.
Yep, got it. A quick look at Napa online showed $27 and a few dollars to ship from the warehouse to the store (they don't stock it and seem to like to charge to have it sent to the store overnight). I may see if my local salvage yard has one to get me going. I did a little research and found that any 7.3 from '94 to 2001 will work. If the price is right I may go that route since they warranty their parts for 150 days--by then I will have the Stancore. Just a thought if it is less than the Napa price.
When you "cycled" the glow plugs, did you turn the key off and back on when the WTS light went off? If so, that's a complete waste of time. The glow plugs remain energized long after the WTS light goes off, up to two minutes (that's why it's a WTS light and not a glow plug light). Just leave the key on to run the glow plugs longer.
But it's for that reason that it's not just the current draw of the glow plugs that is demanding on the relay. The long run time is even more demanding than the high current. There are lots of relays out there that will handle the 100-plus amperes that the glow plugs draw, but are rated for a closed time of just seconds. The Western Plow relay doesn't list (IIRC) its closed time rating, but plow motors only run for a few seconds at a time. The Stancor is related for continuous closed time.
When you "cycled" the glow plugs, did you turn the key off and back on when the WTS light went off? If so, that's a complete waste of time. The glow plugs remain energized long after the WTS light goes off, up to two minutes (that's why it's a WTS light and not a glow plug light). Just leave the key on to run the glow plugs longer.
Yep, I cycled the key. You just educated me--thanks!! UPDATE>>>>>>>>>>> I picked up a used relay yesterday from a '99 truck. I now start instantly This one will keep me going until I can get a the Stancor one ordered to keep as a backup--that, if history repeats its'elf, wil be within 2 yr.
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Going Through GP Relays
97 F250HD SC SB PSD ZF 5SPD 4X4 OFF ROAD 230K CHROME GRILLE GUARD GOOSENECK WARN MANUAL HUBS LUK SMFW KIT FIRESTONE AIRSTROKE AIRBAGS OTHERWISE STOCK FOR NOW 
This one will keep me going until I can get a the Stancor one ordered to keep as a backup--that, if history repeats its'elf, wil be within 2 yr.
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