128 owners Relay HELP

P

pdxgeo

True Classic
Split Pea has 2 relays that are BAFFLING the heck out of me. They are bolted in tandem behind the battery on the strut tower. I will call them #1 and #2 and they are wired as follows:

#1-
grey/Yellow to #86
Brown/white to #85 which jumps to #30
Brown white at #30 jumps to #30 or relay #2
Blue/black to #87 jumps to #87 of relay #2

#2
Red to #85
Brown white from relay #1 to #30
Blue/Black from Relay #1 to #87
White/Black from #86 to ground

So it seems since only one wire goes visibly to ground that perhaps they are made to operate in tandem somehow but WHAT are they for? the only wire I can sort of trace is the grey/yellow off relay #1 which seems to go to one of the sending units (oil pressure i think)... The wiring diagram has SOME of these colors shown but NO brown/white at all. I am wanting to add relays for lights/wipers but Id like to understand what the heck i have going on before I start adding/changing things...

Any help would be greatly appreciated. thanks
 
My guess...

These sound like the start and run relays for an electric fuel pump. One is probably energized when the starter is cranked, and the other is energized when the oil pressure light goes out. In this way if the oil pressure light illuminates (as in a stall or crash) the fuel pump stops.

Are you running an electric fuel pump? If not you could ignore these. Assuming my hunch is correct. My Scorpion has this arrangement, but since converting to F.I. it's no longer in use. It took me some figuring to get it working when I got the car, since a previous owner had bypassed it when the oil light switch failed.
 
hmmm, interesting

Thanks Greg, I am not running an electric pump but perhaps a PO had been. I noticed in the wiring diagram that blue/black wire is associated with the 15/54 switch position at the ignition, does that jive with your theory?

G
 
Sorta...

On my car the wires from (87) go to the pump (or would if it was still in use) and the (30/85) and (30) go to the fuse 1 which is powered at the ignition switch. So yours might be "backwards" but it might work the same way.

Your red wire probably is hot when cranking (from the starter solenoid tab) and the oil light switch and "relay 2" ground are the same as my car.

This sounds like a stock setup so it's possible it came with an electric pump or came wired for one despite using a mechanical pump.
 
I might have a diagram. I'll have to see what I have. Some time ago I bought a big box of manuals, diagrams and service letters from another Fiatsi and haven't really gone through them all.

Early Fiats like yours had great, full-color fold-out diagrams in the owner's manuals. If you can find an original owners manual it's a great resource. My 850 Spider's manual had this diagram and it was very helpful.
 
budgetzagato said:
I might have a diagram. I'll have to see what I have. Some time ago I bought a big box of manuals, diagrams and service letters from another Fiatsi and haven't really gone through them all.

Early Fiats like yours had great, full-color fold-out diagrams in the owner's manuals. If you can find an original owners manual it's a great resource. My 850 Spider's manual had this diagram and it was very helpful.
Click to expand...

Hi Greg, if by any chance you also have one for a 75 please lmk....thanks!!
 
I have a '74 "Specifications and Data" book that has a b/w diagram in the back. It doesn't label the wire colors, but seems to follow what you describe.

Sort of. The '74 diagram shows the (87) terminals of these relays (identified as start/run fuel pump relays 121 and 121/1 going to the fuel pump.

Are you sure that on yours the blue/black wires are the ones that are ign. switched and not the brown/white? If it's the brown/white that is ign. switched it would follow the diagram.
 
Factory 1972 128 manual...

...titled "Electrical System Proceduralized Troubleshooting Aid"
confirms 2 relays mounted as described are for OE electric fuel pump.
SplitPea converted to mechanical pump by PO.

Spiffy little manual, GBC bound with diecut tab dividers.
Backcover copy reads:
"Remember our customers are our future.
Lets treat them right."
Interesting it reads pretty user friendly.
More like a DIY guide than a Technician guide.

Only owners manuals I have are '76 & '77.
They have electrical diagrams but not in color.

Also have OE Shop Manual with several large/foldout color diagrams.
Undated, but '73 & earlier bumpers are shown.

Welcome to borrow 'em George.
 
Thanks Mike, I actually have the electrical guide for the 124 Spider and it is among the handiest of all the old literature. Wish i had that one, perhaps i can take it to kinkos and have a GBC bound set made myself...

G
 
Thanks Greg, i found an image of the 73 specific diagram on ebay and just looked at it on my screen. Looks fairly close to what im seeing out there. Did a whole lot of work for NOTHING today. pulled the dashboard in hopes of tracing a severely frayed wire within the harness. Im assuming it was the cause of smoke about a month ago but unless I pull the steering column and cut the harness apart i cant get to it. it is basically cut short already. Theres a real mess of melted plastic around it, i pulled them apart as well as i could and wrapped some tape around the bare one but it does not look good. It's more than I can afford to pay someone and more than I know how to do so it will have to remain that way for the time being. everything works except the hi-beams and Im not sure thats even related. i doubt it from the looks of it this has been a mess for a while and I had hi-beams up until recently...:hypno:
 
Troubleshooting highbeams...

Start with the fuses. Are they good? Do you have power there? Then, check the bulbs. Grounds are good at the bulbs if you have low beams.

Once those are ruled out, trace the green and green w/black stripe wires at the headlights back to the fuse panel. From there the highbeams are on the blue wire to the hi/lo switch, green to the lighting switch, and black to the ignition switch. Use a 12v test light to find where the power stops. Could be any of the switches or a bad connector at one of them.
 
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