I have an 86 f350 6.9. Snowed today in NH went out to plow the driveway and the truck wouldnt start. I noticed when I turned the key the glow plug light was not illuminating as usual. I did hear the relay click once.

I ran the truck the day prior and everything was normal. Everything cycled as normal. The glow plug light came on heard the relay clicking and it started normal.

Was wondering if the controller crapped out or the GP's are fried. Just wondering everyones thoughts on this.

I did eventually get the truck started with the block heater but no GP's cycling still.

Thanks
Lee

 

I haven't gotten into the GP relay and electrical personally yet. In a case like this I would make a jumper lead and go from the battery and touch it to the relay which is right behind the passenger side battery. Dave S. has a photo of it in his gallery of mods, I belive it is a purple wire. IF you put power it actives the glow plugs. Touch it for 10 seconds (no longer!!) then should be able to fire the engine up. If it works then you know the controller isn't functioning normally.

Someone chime in if I am mistaken!

 

You should test your glow plugs first.

 

The only bad thing is the old style controller usually failed by turning the glow plugs on while driving.
That results in burnt out glow plugs.

The wait to start light is down on the dash so far, you usually don't see it on while driving.



A jumper from the battery terminal of the glow plug relay or the battery positive terminal to the purple terminal of the relay will cause it to close.
10 seconds max and the engine should fire.

Test your glow plugs with a test light.
Ground clip on the positive battery terminal.
Remove the glow plug connector and touch the tip of the testor to the spade terminal on the glow plug.
If it lights, the plug is good.
If it don't, the glow plug is toast.
Repeat for the other 7 glow plugs.

If you find they are all burnt, post back and I can run you through how to convert to manual glow plugs.

Motorcraft Beru ZD 1A glow plugs for replacements.

 

I tested the glow plugs today and the test light came on for all of them. I also jumped the purple wire on the relay and nothing. My question is this. When the purple wire is jumped I hear the relay close shouldnt there be power going from the relay down the orange wires to the glow plugs? I tested it and there isnt any power with the relay jumped going to the glow plugs. Is the relay bad?

Lee

 

My 86 info indicates each GP wire has a fusible link, 8 of them..... not heard of any one having all 8 burnt out, but testing the continuity of each wire may be wise....too.

 

If you do not have power at both large posts the relay with the relay jumped, then yes, I would say the relay is bad. Also make sure you have power going to the relay.

 

There is power coming from the battery to the relay. When I put the test light on the post closest to the battery there is power. When I jump the relay there is power on that same post but not the other.

 

That sounds like the relay contacts are burnt.

Mine is finally starting to act a bit funny sometimes, but since it has been in there since 1986 I guess it has done a decent job.
Now if I can just find another one that will last 22 years.

 

Dave the way parts are made now. Good luck in finding a relay to hold up for 22 years.

 

Actually I would be happy if it lasts five years.

I have been having good luck with NAPA constant duty solenoids, I have them on my plow hoist pump, salt spreader and electric/hydraulic bed hoist.

May have to adapt one for the glow plugs.

The only down side is the cost, I think the last one I bought for one of the company trucks dump bed was 45 dollars.

 

if there is a grainger in your area try sk # 6c028 its 12v constant duty rated at 80 amps.(essex white rodgers # 70-111224-5] been running 1 in my 6.9 for 8-10 yrs today maybe 20-25 $ us been a long time. great for use with slo glo [12v] plugs. regards bng

 

The closest Graingers Supply is 120 miles away from me.

NAPA has a couple constant duty relays that will handle the amps.
Even though they want more money, they are still cheaper after you figure in the fuel to go somewhere else.

 

In this area Grangers will ship direct....

 

another sourse is golf car parts ez go uses it on their gas cars [12v] regards