Electrical help

[Jdgephar]

Looking at the picture in the first post, the heat zone appears to be centered around the crimp for the yellow wire.

I agree, it appears that the wire crimp to the terminal overheated.

 

[Steve83]

...this is how I have it wired currently...

This is not a good circuit design. The 12V Bosch relay is redundant, and weaker than the Volvo relay, so it's unnecessarily creating the problems you're having. But as others have noted - your problem was a poor crimp or other high resistance at the yellow wire on the Bosch relay.

...from the battery (pin 87 on the relay, 12V in with a 30A fuze inline)...

That's pin 30 on the Bosch relay.

...Pin 30 (to the Volvo relay).

That's pin 87 on the Bosch relay.

I'm going to bump to a bigger relay...

That's not really an improvement.

The toggle switch at the right side of the diagram is only there to disable the fan (by controlling the Bosch relay) when the key is ON. That can be accomplished by putting that switch (ALONE - no relay or fuse) into the wire from the temperature switch to ground. Then the red wire from the Volvo pin 30 can go through the fuse directly to the battery (but it shouldn't be physically attached to the battery - it should be on the starter relay's always-hot post with the alternator output & feed to the Bronco's wiring). Another improvement is to run the fan return wire directly to the battery (-) or to another ground point (like the main block ground) that has a larger return wire (like the black battery cable) so that it runs through wire the whole way (not really grounded).

 

[Bitch'nBronco]

This is not a good circuit design. The 12V Bosch relay is redundant, and weaker than the Volvo relay, so it's unnecessarily creating the problems you're having. But as others have noted - your problem was a poor crimp or other high resistance at the yellow wire on the Bosch relay.

That's pin 30 on the Bosch relay.

That's pin 87 on the Bosch relay.

That's not really an improvement.

The toggle switch at the right side of the diagram is only there to disable the fan (by controlling the Bosch relay) when the key is ON. That can be accomplished by putting that switch (ALONE - no relay or fuse) into the wire from the temperature switch to ground. Then the red wire from the Volvo pin 30 can go through the fuse directly to the battery (but it shouldn't be physically attached to the battery - it should be on the starter relay's always-hot post with the alternator output & feed to the Bronco's wiring). Another improvement is to run the fan return wire directly to the battery (-) or to another ground point (like the main block ground) that has a larger return wire (like the black battery cable) so that it runs through wire the whole way (not really grounded).

This is helpful, thank you. I did recrimp the yellow wire this morning and drove to work. I do want to improve how I wired the fan so I'll definitely make the changes you recommended. With your notes on the bosch relay, are you saying I had 30 and 87 wired backwards?

This may be a dumb question, but if I remove the Bosch relay and move the fan power wire to the starter relay; wouldn't the circuit be hot all the time? Or does that not matter since I have the thermostatic switch that completes the ground to the Volvo relay? Currently, the Bosch relay is wired to my ignition switch and closes when i turn the key.

 

[ntsqd]

Power to the Volvo relay would be hot all the time. That's a non-issue because the control gets switched on and off with the IGN. My '84 Rabbit diesel ran the cooling fan whether the IGN was on or not. If the sensor said it needs to run, it ran. I wired the electric fan on the Ranchero to work the same way.

 

[Bitch'nBronco]

I like that idea. I think I'll do that. Thank you

 

[Oleguy 74]

to keep things normal,+ 12v on pin 30 and pin 87 to the fan or whatever the load is.pin 30 and 87 are normaly open.they close when relay is operated.also use dialetric grease or noox om the relay contacts to prevent corrosion.

 

[Bitch'nBronco]

Power to the Volvo relay would be hot all the time. That's a non-issue because the control gets switched on and off with the IGN. My '84 Rabbit diesel ran the cooling fan whether the IGN was on or not. If the sensor said it needs to run, it ran. I wired the electric fan on the Ranchero to work the same way.

Was your thermal switch on the radiator or intake manifold? Mines on the intake manifold, and was thinking the fan would run for a really long time, key off if I don't have anything circulating the water from the block to the radiator. The rad would cool way before the block.

 

[ntsqd]

It was at the radiator inlet on the Ranchero and in the hot side radiator tank on the ribbit.

So long as the coolant temp is above the t-stat's setting the t-stat will remain open. That sets you up for "thermocline circulation', some old tractor motors worked this way. No water pump, the difference in coolant temperature drove the coolant circulating thru the system. As you might guess, it's not a high volume pumping situation, but it does move the fluid.
Once the t-stat closes you still get some conductance cooling from the hotter coolant in the block trying to heat up the colder coolant in the radiator via the fluid connection in the lower radiator hose. By this point to cooling rate is pretty slow because the temperature difference isn't all that great and it is progressively getting smaller and smaller.

 

[Steve83]

...are you saying I had 30 and 87 wired backwards?

No, I'm saying you were referring to them backward. I can't see how they're wired - only how your diagram showed them, and what you said about that diagram.

...if I...move the fan power wire to the starter relay...

Don't do that. The fan power wires STAY where they are on the Volvo relay. The way my diagram shows, the fan will continue to run if the coolant is hotter than the temperature switch (wherever you have that switch mounted) until it cools, or the battery dies. But to kill it at any time (even if the engine is hot), you just flip the toggle to OFF. But then you have to remember to flip it ON again before the engine overheats. So the fan should move air across wherever the temp.sw. is mounted.

Currently, the Bosch relay is wired to my ignition switch and closes when i turn the key.

Does that mean the toggle shown in your 2nd diagram represents the ignition switch? Since it's labelled as coming from a switched 12V source, it appears to be an additional toggle you added to the Bosch relay's trigger circuit, being fed by the ig.sw.

...use dialetric grease...

Never put dielectric grease on anything that you WANT to conduct electricity. Use electrical grease (which is not conductive) to slow corrosion.

 

[Oleguy 74]

you did not read part about no-ox grease

 

[Viperwolf1]

you did not read part about no-ox grease

He doesn't understand dielectric grease. I've tried to explain it to him but sometimes you just gotta let people think what they will even when they're wrong.

 

[Steve83]

you did not read part about no-ox grease

Wrong, I just didn't COMMENT on it.

He doesn't understand dielectric grease.

I understand what Ford says about it, and I understand what the word "dielectric" means. Its electrical resistance increases as the voltage across it increases, sort of like non-Newtonian fluids becoming less-fluid as the force on them increases. That's the opposite of what you want to happen with an electrical connection, which is why Ford doesn't recommend dielectric grease on electrical terminals - they recommend electrical grease. It prevents corrosion but doesn't inhibit current flowing between the terminals.

 

[Bitch'nBronco]

No, I'm saying you were referring to them backward. I can't see how they're wired - only how your diagram showed them, and what you said about that diagram.

Don't do that. The fan power wires STAY where they are on the Volvo relay. The way my diagram shows, the fan will continue to run if the coolant is hotter than the temperature switch (wherever you have that switch mounted) until it cools, or the battery dies. But to kill it at any time (even if the engine is hot), you just flip the toggle to OFF. But then you have to remember to flip it ON again before the engine overheats. So the fan should move air across wherever the temp.sw. is mounted.

Does that mean the toggle shown in your 2nd diagram represents the ignition switch? Since it's labelled as coming from a switched 12V source, it appears to be an additional toggle you added to the Bosch relay's trigger circuit, being fed by the ig.sw.

Never put dielectric grease on anything that you WANT to conduct electricity. Use electrical grease (which is not conductive) to slow corrosion.

Correct, I dont have a toggle switch. Im using the ignition switch in its place. The there's no (less of a chance) forgetting to turn it on or off.

 

[ntsqd]

As an engineer who designed sub-sea submersible electrical connectors, putting dielectric grease on the contacts is fine. If the contacts are doing their job correctly they 'wipe' any oxidation on the mating surfaces off when the contacts are slid together. This is a design function of all connectors and mating electrical contacts. Which is followed by a mating force that is high enough to conduct electricity across the contacts with low resistance. (There's a very good reason why those Anderson fork-lift/winch connectors have such a high make/break force.) Which means that any dielectric grease will have been removed from between the actual surfaces in contact while remaining in place all around them to reduce or eliminate the opportunity for oxidation to occur. Unlike dielectric grease, oxidation can work it's way into the mating surfaces if unprotected.

Contrary to at least one person's opinion, Ford engineers are not God and do not know it all or are infallible. There's attempting to understand the design intent, and then there's kneeling in supplication while facing towards Dearborn.

 

[DirtDonk]

Seems to me that, for most of our automotive (or marine) applications at least, electric grease is contra-indicated. (if that’s the proper phrasing?)
Since its function is literally to conduct electricity, it would be best used in a single conductor connector. Not a multi conductor connector, or one that could be near bare metal.
Or, as would seem to always be the best practice, use the minimal amount needed to get the desired result.
Of course, it’s up to the Installer to not use too much grease either way, but if it’s ever allowed to squeeze out when the two halves of a connector are joined, or ooze out from heat/pressure, it then becomes the conductor itself. Possibly allowing the outside of the connector to be conductive. Or worse still, adjacent conductors inside the housing to be shorted together.

Dielectric grease on the other hand, doesn’t have that problem and, as described above, since a properly working connector has sufficient friction connection (again, if that’s a proper term?) then it would be perfectly fine.
Perhaps microscopically getting where it does in fact block some conduction that would otherwise be present in a dry connection. But not enough to render the connection inoperable.

Either way, for us, the grease is simply to seal the metal connections from air and moisture, that what other wise result in long term oxidation.
Oxidation seemingly being the lesser of two evils, between slight loss of conductivity over time, and short-circuiting/cross connecting between circuits.

Does that seem a reasonable separation of the two uses?

 

[ba123]

Use whatever works for you...

I like Dielectric grease on certain terminals to keep out corrosion. Those terminals conduct electricity on their own, I do not want the grease on the terminal to conduct outside of that connection, so the grease is simply to protect the connection.

And, just like Steve83 wrote, I use conductive grease on the Alternator bracket to maintain conductivity between the two and maintain ground.

I'm not as cool as Steve is so I don't have a Motorcraft one, but I have this one:
https://mgchemicals.com/products/gr...trically-conductive-grease/conductive-grease/

 

[ntsqd]

Most alternators have a threaded boss on the back of them. The belt and suspenders approach is to run a ground cable of the same gauge as the charge cable from that post to the battery. This is more often done in deep water marine applications than anywhere else that I've seen. It is what I will do should I ever need a large output alternator (say over 150A) and it has crossed my mind to do it on a couple vehicles with lower outputs than that.

Ford lists the XG-12 electrical grease as conductive, but according to one poster here it is not: https://bobistheoilguy.com/forums/threads/motorcraft-electrical-grease-xg-12.263989/
I would be inclined to only use it where a silicon grease is undesirable for some reason.

 

[EPB72]

I like that idea. I think I'll do that. Thank you

In the OE application the HI low speed 3 wire fan was supplied power through a 50 amp fuse ,, which then went to the constant control relay module [CCRM] this was a hot all the time circuit, the CCRM also had other duties like fuel pump, AC clutch but used different fused input ,,,,the volvo relay was good replacment for the CCRM as it controlled the two speed fan the same way the CCRM did but simpler, as well as handling the current of the taurus fan,

 

[ba123]

Well, so far, my 200 amp single wire gen 4 alternator is working great the way I set it up and I expect it to continue that way. I do have a ground directly to both the bock as well as the back of the head though and did measure resistance before I installed the alternator.

 

[EPB72]

Well, so far, my 200 amp single wire gen 4 alternator is working great the way I set it up and I expect it to continue that way. I do have a ground directly to both the bock as well as the back of the head though and did measure resistance before I installed the alternator.

exlorers never had the grease on the mounting of the alt,, untill they used the 4.6 modular engines or earlier expeditions , you would see the grease then later on that seemed to disappear ....
FWIW 130 4g alt will regualrly test upto 160amps 9 times out of 10,,,,,I find the grease is mostly only benifical during assembly to allow smooth full engagment of the terminals and the locking connector ,, greased or ungreased I've worked on thousands ii'd say inconclusive,, GM exterior lighting used greased sockets plenty of issues there,,,, terminal tension seems more of an issue and grease dosen't cure that,,maybe temporarly,,,