Good Morning, Greg...

Interesting. For this job I purchased a large number of large flat neoprene rubber washers and a large number of basically fender washers that are as you describe. Good. I'll go to McMaster Carr and order a bunch of zip ties and do as you suggest...

I think my problem now is ME... Although I think the problem I'm having, the reason the fan started running like it did, is due to a shorted sensor due to water intrusion. I don't think the damn thing is water proof! In refilling the coolant system yesterday, sensor being at the bottom of the rad exactly UNDER the bleed hole, I think that water ran down the front and side of the rad right into the damn sensor. I would guess the sensor works on a resistance value similar to a CTS. As resistance decreases it is interpreted as heat, blah blah blah. If water got into the sensor, shorted it, the sensor MAY be telling the controller the car is hot...? Sounds plausible.

I'm going to remove the sensor this AM. See if that stops the fan, have a look at it, dry the damn thing out if need be.

​​​​You know how the internet is... People LOVE to give a bad report. Thing is, I could find NO bad reports about this controller. Lots of folks using them on hot rod street cars and for DIY weekend race cars and stuff.

If you would, and it doesn't take ANY of your time today, if you have a pre written write up thatvis, YES, I'll take it. If it will cost you some time today, hold off, and let's see what I discover today in my digging.

 

No bother, here it is. Basically, the small fan runs with the aircon compressor. If you do not use the aircon, what with being a convertible, wire the small fan to be on with the ignition - post for details if you decide to do this.
For the main fan you need 2 x 70 amp relays (lower amp ones get fried on startup of the fan). One for the cabin switch, one for the automatic circuit that is triggered by the OEM water pump inlet switch. Also one fuse box for the power feed taken from the firewall post, one for the other low power circuits (ignition-on triggered circuit, warning light circuit, etc).

 

Not sure if this confirms or refutes ANYTHING. But, if I plug in the fan with the sensor connected,,, fan comes on full blast. If I disconnect the sensor, no fan... I'm going to remove the sensor (2 sided super sticky 3M tape) and see what I see,,,

Removed the sensor. Removed adhesive tape and padding from the two sides. See below. There are two distinct "sides" to the sensor. Now I get ZERO continuity at points across the sides/halves of the sensor now. If I plug the sensor in (unlike before) I get ZERO from the fan...

If I bridge the two solder points with a bit of metal, where the wires come into the board, I get full blast fans.

To me, this is pointing to the sensor, lol... I guess it doesn't like water? Why make a thing as fragile as THAT?

 

Forget the electronic crap JJJ, why do you think I predicted they would inevitably fail you at the worst possible moment? Your bold reply was "I'll just wait by the roadside for the AAA"! Now the Jaguar Gods like you, which your hard work and great achievements thoroughly deserve, which is why they showed you the reality of an unreliable fan control system now, parked up outside your house; but like the Old Testamant God, they will not give you a second chance...
Imagine the following scenario: You and La Bella are enjoying an evening supper on a restaurant's veranda overlooking Long Island Sound, a couple of glasses of white are going down beautifully with the soft shell crabs; she says "let's cruise home in the twilight over the Verrazano Narrows Bridge". Time has flown and it is nearly dark and you have been enjoying your evening for several hours. Hand in hand you wander to your beautiful car, open the door for La B, and settle her into the passenger seat. Elegantly settling into the car, you turn the key, having subliminally registered that the courtesy lights did not come on when you opened the door. With sinking heart you realise the battery is dead, flat as ink. La B's irritation starts to surface as you open the hood to place a hand on the red hot controller and the awful truth dawns.
Then those terrible words appear on the inside of the hood, written with a silent disembodied hand:
"Mene mene tekel upharsin"

You have been weighed in the balance and found wanting...

 

Damn it, Greg, lolololololol...
I'm on the next flight to France! Imma GIT ya!
Then I might jus head to Australia,,, GIT me a piece of GF too! Hahaha

Ok, ok, I'm on it... I have 2 new 12v triggered 80amp relays on hand,,, cuz I knew this day was coming...!

Been real pleased with the portable solding iron, too!

In the mean time, give me nuts and bolts any ol day. Just dropped and reinstalled my leaky RH down pipe. Amazing how much LOUDER the sounds in the engine bay are now that that mechanical fan ain't howling...

Gotta keep it move'n!

 

I'm willing to spend some.
Does anyone know of a high amp alternator for our cars?

 

JJJ
You told us that you already had a 115 amp alternator. This will do the job, no bother.

 

Hey. Good morning.

I took the 12v for the 16inch fan/80amp relay directly from the main LH 12v post at the fire wall but am having some unexpected symptoms.

At this point I have the 16 inch fan wired in (not the 12 yet, I haven't been driving, just testing at idle). I used the relay trigger wires from the old small E fan to trigger the new 80amp fuse when the pump housing ThermoSwitch gives the signal. Seems to engage the fan a at a cooler temp than before, but maybe that's my imagination.

The fan is grounded ALONE, 10ga wire, eyelet, at one of the two bolt downs for the radiator support at front corner of engine bay. I had the fan grounded it at one of the 2 main ground points at the fire wall. But both of them ground other major systems and I thought this common grounding might be causing the issues described below.

(The LH 12v post has a set of wires/eyelets that run into the cabin to power dash - and fuse panel)

For one, at times, the idle pulses. Up and down roughly 200+ rpms. I don't know why... This wasn't happening before. Sometimes it doesn't happen, sometimes it does.

Two, trip computer is reading 8888. Was working perfectly before. To me this is something I can SEE, indicating there are probably other things being effected that I can't see.

A couple of the dash lights (LEDs), brake and oil, remain on super dim, but this wasn't happening either.

I haven't looked on the RH main 12v post to see what else is wired to it directly, with an eyelet, like the LH 12V post. But maybe, if its a naked post, I should use IT, rather than the LH hand post which powers (I think) the instrument cluster and cabin components???

About the alternator. I do have the 115, it's fairly new. When the fan kicks ON (just the one) I get a real drop in voltage. From 14 or 13.9v down to 13v. It then recovers some ( to13.4v)... But with lights on, heater fans on, brake lights on, it struggles. And this is without the small fan. If I had a 170, 180 amp I wouldn't have to worry about any of that. I would like a stronger alt,,, if they can be had.

 

Lot of stuff going on here and a truck load of unknowns, this is one of those areas where changes can cascade, you fix one then another in the chain breaks.

First the alternator current means little, this varies with engine speed, it won't produce 115A at tickover. The voltage also seems a little 'low' at 14, I'd expect 14.7, you also need to be sure the battery is up to snuff - if you don't increase the Ah of the battery when doing the alternator you put a lot of load on the alternator - the battery should be able to function as a buffer - if your lights dim when the fan kicks on you aren't producing enough juice. It could be that your current alternator needs to be re-pullied but now you're getting into serious engineering because you can't exceed an rpm max of the alternator.

Grounds particularly for high current systems should always be as close to the load as possible to minimise losses due to cable runs - and grounds for high loads if possible are better put through braided lines than sheathed cable. Measure the resistance if possible in your ground path, the closer to zero the better.

Doesn't matter which post you use - they're linked across the bulkhead but the one closest the battery would be the preference - and I think you will find that is the LH one.

You can get a hi amp alternator like you mention but how often are you going to load things down so heavily because it is going to cost you and you may need to source new pulleys across the board - such alternators ideally need poly V belts, the alternator should ideally have an overrun clutch - you will also spend a significant amount - here is an example High Amps

Too many wire heavy induciton loads such as fans without understanding how they behave when you switch power - they can kill electronics pretty fast so some sort of flyback diode if not already in place within the motor needs to be added to prevent spikes and back feeding, if you switch to often induction loads can create very significant voltages and current. Flyback management

 

JJJ
The main fan should be earthed at the securing bolt of the radiator top panel, RHS rearmost of the two. Your symptoms sound like earth feedback to me (ie current going up to a device via its earth wire). Also ensure the earth connections on the RHS frame by the battery (lift the carpet and that trim covering the relays etc and you will find them) are bright and clean, see next para.
Did these symptoms happen with the earth wire at the firewall or at the radiator top panel? ALL eaths must be showing bright metal, the connector and the body, then attach the earth, then spray with white grease to exclude corrosion.
The instrument panel and all interior 12v sources come from the firewall posts, but the INSIDE side of that post. There are also LOADS of earth wires on the frame strengthening pillars that run up each side of the aircon unit. Impossible to clean these without removing the dash; but poor earths at this point would affect your electrics for sure if you introduce a huge "to earth'" current nearby.



Earth connections from loom to the frame to the battery, and from the frame to the battery, including the main battery earth strap; cleaned to bright metal and attached.

Coated with white grease.

 

Next point. As Ben said, an alternator as big as a power station will not produce current at tickover! Your volt numbers are fine. If you remember, that is why I have a connection in my diagram to the OEM extra air solenoid, which I have repurposed to come on with the fan, rather than the aircon compressor. This gives a tickover of about 900 rpm in neutral and keeps the volts up.
If you have lights, wipers and fans all on togther at what would be a normal neutral a tickover of 750 rpm, then the only way you will keep volts up is by extra revs. How often will this occur? If you are seriously worried, fit a couple of extra air solenoids, one automatic from the fan and one cabin switched.

 

Hey Greg and Ben. Thanks.

I didn't touch the car today, spent some time thinking. I also was thinking my problems were earthing problems and I'm going to that, and just that, to start when I get back into the car.

I was also thinking (unless electricity just doesn't work this way) that the 3 eyelets on that one 12v main post on the LH (US car) side might not like living together and sharing. On my car it LOOKS like that post feeds coils and ignition amps and such (I think) I need to take a closer look. I might try switching it over to the other side...post

Yes, I have my concerns... I am also sure that they are solvable. Already, I am pleased with the results. I'm not in a rush, a panic or anything. Just need (with y'all's help) to work things thru.

Still, I am in the market for an alternator that can give me more amps. I can't see how it can hurt, and don't understand why anyone would dissuade me from going in this direction. If I could find a trusted source for a 140amp alternator, I would take it. I don't want to be taxing the alt that I have everytime the fans kick on. I can feel the engine hiccup when the fan finally does kick on from a dead stop. I don't like it. I wish there was a product that could just control a sloooow start to full speed - even if it's not a controlled PWM set up related to temps. Anything. I have read thru lots of stories in random auto forums where folks are wrestling with and trying to solve the problem of dead stop to full speed with electric cooling fan mods,,, and the power drops that accompany this. It's a thing, for sure.

Anyways, I'll get there, figure something out, no doubt.

 

I need y'all's eyes... Will this at least solve the HARD start issue? I would at least like a softer slower start up...

I THINK what this guy is saying is that at start up,,, it never goes higher than a 24amp draw,,, as opposed to like 100! (from what he says?) at a HARD 100% full start.

Thoughts?

You Tube

 

I read somewhere that this one works reliably: but no actual experience of it. Best to locate it in the cabin!
https://www.autocoolguy.com/home

Greg

 

Hello, Man. Yeah, I've seen this guy's stuff, and his videos. I was thinking to give him a call. Thing is,,, I wasn't thinking this was going to end up a 400 or 500$ thing, at the end of it all... For Darrell at AutoCoolGuy, I've heard nothing but good.

I guess it would be the 200$ unit with feeds for 2 fans. We shall see.

 

JJJ
You are trying to create a system that works like a modern one as as reliably as a modern one; it can be done but it costs money. Now, I have had an electric main fan since about 2002, it starts and stops as required and does not make the car cough or hiccup when it cuts in using all its 27 amp glory. In principle a PWM device, if reliable, would be nice for you; but such things costs money, time, and what is the cost/benefit?
The hardest decision when launching a new car is when to stop developing it and to start making and selling it. This is, in essence, the dilemma you are facing!

 

Thanks for the thoughts, and the questions, Greg. Really! The questions you ask help me think about things in ways that I wouldn't have.

For me, to use a phrase, these are luxury problems, of sorts. My regret is that I take y'alls time with all my questions, stops, problems and searching.

That said, I think about MY driving conditions, where I'm using this car, what season and for what reasons. Often, summer, OFTEN traffic, often hot and tooooo often slow. With those conditions, for a few reasons, a fan that is continuously starting up and cutting off, over and over in one drive, doesn't sound like fun or good for components or the car. If I was looking at long miles of rural or suburban driving, ok, sure. But that's not my situation.

Costs and Benefits questions. Yeah, them things... I would like a smooth start up and shut down of fans. From everything I've read, the START of a large fan (which is what I'm worried about) can be upwards of 70, 80, 90 even 100 amps, then - before settling down to 25 + 10, in my case. I like the slow start no matter what idea - up to full speed - sounds ok and like a good option (maybe better for some) but if I can do it reliably, considering my driving conditions (in and around NYC) I would LOVE both fans working at a rate and frequency exactly needed for the circumstances...

I LOVE the car... And want to use it worry free (as possible).

The money, that will ALWAYS be a problem (especially with a fleet of project cars), unless it's not. Looking at NEW jobs with better pay (Bella want a new house) as we speak. 😐

As always. Grateful to and for you. Hope you'll stick with me, lol...

You're a gift here, Greg. But you know that already!

 

JJJ
It is a pleasure to help; and I have plenty of that sort of time which is not money!
I can tell you that when I did my rebuild I was pestering Grant, and kind friends in the UK, all the time!

 

Thank you, Greg...

Feeling like Christmas morning over here in Staten Island... Now where am I going to TUCK, this big ol thang???
Behind glove box insert? Fat chance.

 

So, I think I found where this device will live, OUTSIDE of the engine bay, out of site, yet accessable.

I had been thinking on it and some days ago I started in removing the glove box, under tray knee bolster thing - and stuff. I'd watched a few YouTube videos about the ACG HF-125 to try and get a sense of it's size, not easy. Getting it in hand, the thing is big, heavy-ish, and I hope that is a indication of it's,,,, robust-ness as a device.

Anyways, there is a plate that bolts onto the LH HVAC blower motor. I'll attach a photo. It's strong enough to easily support the unit. Close to a GOOD ground/earth and other needed electrical connections. I'll line things up, place it, and get a sense of it's permanent home with some HD 3M 2 sided foam, then remove the plate and use steel fasteners to bolt it to the plate, then remount to blower with the OE 11mm nuts.

I have a few worries. I'm not so concerned about the couple few relays that were held by the bracket/plate (I can find a home for them), I AM worried about the two damn bulb failure units that were attached/screwed to it. They are 30+yrs old and fragile (in my mind)... What I think I might do (3M foam 2 sided is strong stuff) is find a place and adhere them to the plate somehow, or even the side of the auto cool guy box. Or the blower motor. Somewhere.

For the glove box. I intend to make a few SURGICAL AND STRATEGIC cuts (lol,,, I ain't surgical or strategic), get my heat gun and try refolding some of the corners and sections with a small cut out that will allow me to reach at least the HF-125 control knob for temp adjustment. The box will be smaller, but I don't store a lot there anyways.