Electrical 87-89 Low Fluid Light Module Install

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
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87-89 Mustang GTs came standard with a fluid warning light pod on the right side of the GUAGE cluster. LX cars had the same display window, but these lights were not functional as they are missing a few key components.

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For you LX guys that have that low fluid warning pod on your Guage cluster pod and want to get them working? Here what you do? This activates the "low fluid" warning light cluster.


First off, you need to find the warning lights themselves. Only 87-89 GTs had these.

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Now, affix this to the bottom of your cluster. You'll need to use two additional screws here. The original hardware is the same as what secures the cluster lens on, but I don't have a source for these. Pull one out and match it up at your local hardware store...or raid your coffee can of misc screws and see what you have
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Flip it over and connect the ribbon cable. The plastic shoulw slip over the three protruding pins as shown below
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Now, for this to work you need one additional part.

For that, you need to track down a "low fluid module" part number E7ZZ-10E850-A out of an 1987-89 GT.
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Where does it install? Flip down your glovebox and look over the left side where the light it. Should be a grey and green plug mounted to the dash bar. Connector C243 and C244 in this diagram (view from behind dash outwards).

Scroll down to post #6 where i have some photos of the location.

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Remove those and plug into the module. Now, the low fuel light should work.

In order to get the low coolant light to work, you now need to add the coolant sensor for an oem bottle. The 87-89 sensor is different than the 90-93 sensor. If you want to use a 90-93 bottle and sensor, you need to wire the low coolant plug connector like this method outlined by LMR



Low fuel warning will now work with no additional work.

Low washer fluid will work if your bottle contains a low fluid sensor. Mine did in my '88 LX. Others have confirmed this was already present on their cars as well.

Check oil is now wired in parallel with the existing light in the cluster. No additional work needed here, and now you have two warning lights for oil provided you are still using the sensor in the pan.


Parts needed:

Warning light cluster, screws and ribbon cable

Low fluid module
E7ZZ-10E850-A


87-89 Coolant bottle plus sensor or 90-93 bottle plus sensor with rewiring

The low coolant and low washer fluid switches are normally open. Leaving them unplugged will disable the light. When a low fluid situation occurs, the switch closes and the light will come on. If you light stays on constantly, it’s an indication the switch is stuck closed.
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Nice write-up. [emoji106]

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I have an array of 87 thru 93 gauge clusters and a parts car that I think is a 91 I will look to see and will start keeping those things in my array of junk er stuff that someday will be needed by someon. Are the wires part of the harness or separate?
Nice write-up. [emoji106]

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I have an array of 87 thru 93 gauge clusters and a parts car that I think is a 91 I will look to see and will start keeping those things in my array of junk er stuff that someday will be needed by someon. Are the wires part of the harness or separate?

This particular setup is unique to 87-89 only as the GT model had the extra warning lights.

They moved the low coolant light to the cluster in 1990, and I think it's wired differently.

The wiring in the 87-89 is part of the dash and main harness



Honestly...save everything. Check eBay for value but everything fox had gone up. I throw nothing away these days

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Never updated the location.

Terrible pic, but should help you get a sense of how it mounts. Drop the glovebox down (or remove it). On the left side top, you'll see the metal dash brace. It bolts to the topside of this brace.

You can see it here, with the dash removed.

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Another pic of it on the dash frame

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I found a low fluid module on line and started this install, the first item I tackled was the low washer fluid portion.
Come to find out, I already HAVE the low washer sensor in my 4cyl '89 LX. But I put the new one in anyway. My suggestion is to do the washer fluid LAST, and test it BEFORE dumping $1xx on the reservoir/pump/hose/connector.

But great write up, Thx!

The washer reservoir had an "E4" date code!