HOW ? Want to put in a low coolant sensor from scratch

[Baron VonZeppelin]

I want to put in a low coolant indicator in my 81 Truck - from scratch. It didn't come factory with such equipment.

Need Help.

What i have:

1. New expansion tank and new in-tank coolant sensor
2. 2pin plug  for sensor with length of wires (from an mk2)
3. An indicator light that blinks when activated (aftermarket)

The indicator light will mount in one of the lower dash bezel blanks.

I don't have a clue how this deal should be wired to work.
I have an mk2 with working coolant sensor - and that doesn't help me really at all. With switch on (or engine running), I unplug the wiring plug from the sensor - and it flashes the dash light. Okay Groovy. At that time - on one of the wires i get a ground reading, on the other wire i get nothing as far as a negative or positive reading.

So right off the bat, i'm lost on this.

Can anyone put it in layman terms and plain english what I need to do to make this fiasco work on an 81 Truck ?

I have access to numerous mk2's right now in boneyards if i need to get some special pieces from them, to do this operation.

Many thanks for some help

 

[Vincent Waldon]

Yeah, the factory coolant sensor has some interface circuitry, rather than driving the light directly.  It measures the impedance of the coolant in a manner that also prevents the probes from corroding. 

Fatmobile built up a circuit once iirc... might want to draw his attention to this thread.

[Baron VonZeppelin]

Thanks Vince, i will try to pm him tomorrow.

[fatmobile]

Here's my for sale post:
http://www.vwdieselparts.com/forum/viewtopic.php?t=6914&highlight=coolant+level

[Baron VonZeppelin]

Super Cool    

I'd call you a genius on this item Fatmobile, but then some wizard would pop up and start explaining how simple it is to scratch build one - and I'd be more lost than before.

I'm good for one - DEFINITELY !
Will send PM later tonight on that, and the hubcap.
Good to go on both items.

Checked out all the links on it.
Should be able to handle this with some small guidance on a thing or two.
I've already had mk1 clusters about 90% apart swapping a fuel gauge and a speedo repair.

Any problem doing a dash cluster LED *and* the blinking indicator i bought, in seperate locations?
I'd like to have both, and both working.

I lost a good engine in the mid 90's about exactly to how yours went, that inspired your invention.
Sold car cheap after that. Was a mint 80 Celica GT.

With your device, this whole system can be installed with all NEW parts for around $35 - on any Mk1 Diesel that doesn't have a capped type radiator.

That's cheap insurance where i come from.
Thanks man.

[Baron VonZeppelin]

I got my circuit from Fatmobile, and installed it this week.

It was easy to install and it works GREAT !
Very Very happy camper.
Many thanks to Fatmobile for his work and supplying this much needed item.

I'm going to do a walk-through pictorial for dummies (my level and lower) on the install sometime soon.

You can go with his supplied internal dash cluster Red Flashing LED - OR if you don't want to go into the cluster - you can buy a remote external flashing LED from Oreillys for $5 and put it wherever you want it.

I went with Both.
So i have an indicator in the dash cluster - and another indicator above my ashtray (in one of the block offs - next to hazard flasher switch).

I also upgraded to the multi-color/color-changing Red-Green-Blue LED for the internal dash cluster ($2 from Fatmobile). Its WILD !

Many many thanks Craig !
I'm truely happy with this system and the extra peace of mind is very valuable to me.

[fatmobile]

Glad you like it.
 You are the first person to buy one.
 All my Rabbits have them.
 I ran out of coolant once and fried an engine so I mostly built them for me but figured others would be interested.

[Baron VonZeppelin]

Amazes me I'm the only person who has bought one.
I'm beginning to wonder about some of the "others". lol

Just the number of Truck owners here is staggering, not to mention pre-83 Rabbit owners.

They should all easily realize how important this device can be to their investment. And you made it so affordable and easy to install its almost too good to be true.

It needs more publicity, i think.
Maybe not exactly so much for your sake (doubt you'll get rich on $20 a throw), but for the sake of those who would buy and install if they were made more aware.

In the next 2-3 weeks should be able to do a write up pictoral on it. Have pix already and the text is no probo, but i have to go to the library to get on a hi-speed ISP to upload the pix to a hoster.
That part is the hold up. Lot going on right now and a big trip coming up.

Damn good job Fatmobile.

[Rabbit on Roids]

it would be cool, no doubt, but i check my coolant darn near every day..

[Baron VonZeppelin]

Its the next best thing to having a closed circuit camera on your expansion tank with a flat screen in the dash. 

Short trippers can check all the time and play on the edge.
Daily distance drivers are suspectible to anything at anytime.
All my cooling system is brand new, even clamps and metal dist pipe. Except for existing low mile water pump.
But ... who knows whats in the road or around the bend.

This thing even lets you know your coolant level is okay at start-up. If it blinks when key is turned on at initial start-up, you're good to go. If it doesn't - coolant is low.

If it starts blinking while driving - you either have lost coolant, or you are overheating. It is 3 detectors in 1.

Like Fatmobile, I have lost a damn good engine before in a car that had no coolant level warning. The gauge didn't alert because it had lost its coolant from a lower hose split. Must have been something in the road ? idunno. Everything was fine until about 35 miles down the highway.

sweet 80 Celica GT hatchback. gone.