Temperature Gauge fix help (Page 1/1)
fierorestore85 SEP 29, 02:55 PM
Hi! I am trying to fix the temperature gauge of my Fiero GT 1988. I know how to switch the sender cables, but I don't know which cables to switch on the back of the dash. Does any one know how to do so? Do you have any diagram or maybe some pictures that could illustrate this and that might help me solve my problem? Thanks in advance!

[This message has been edited by fierorestore85 (edited 09-29-2019).]

olejoedad SEP 29, 03:21 PM
The easiest way to keep the temperature gage from pegging at KEY ON is to find the two small diameter light green wires on the ignition switch on the steering column.
Cut the wires and splice them together so they are not connected to the ignition switch.
Alternatively, you may pull the contact from the plug and wrap it.

That is all that is needed. Nothing to do in the engine compartment or anywhere else.
Camel SEP 29, 04:52 PM
The original fix from "Fiero Sails":

Fiero Temp Gauge Fix
olejoedad SEP 29, 05:27 PM
The Fiero Sails fix works great too.
The only problems with it are the engine wiring harness wire colors no longer match the FSM wiring diagrams, which may lead to confusion to someone down the road, and that it is overly complicated.

Using the fix I outlined above is simple, keeps the wiring harness untouched in the engine bay and prevents confusion down the road for.someone.
If it is desired to have the HOT light illuminate at KEY ON, it is a simple.matter of running a jumper wire from the cut leads on the switch to the wire for the HOT light.
theogre SEP 30, 01:04 PM

quote
Originally posted by olejoedad:
The Fiero Sails fix works great too.
The only problems with it are the engine wiring harness wire colors no longer match the FSM wiring diagrams, which may lead to confusion to someone down the road, and that it is overly complicated.

Using the fix I outlined above is simple, keeps the wiring harness untouched in the engine bay and prevents confusion down the road for.someone.
If it is desired to have the HOT light illuminate at KEY ON, it is a simple.matter of running a jumper wire from the cut leads on the switch to the wire for the HOT light.

Yes, Can cut the wire to I-switch wire to the gauge...

"The only problems with it are the engine wiring harness wire colors no longer match the FSM wiring diagrams, which may lead to confusion to someone down the road..."
Right. Not.
Nearly no-one will notice wire color change if you switch wires per above PDF etc. Including nearly all "pros" including 99.99+% of GM dealer service shops and ASE holders hired by Pepboys and others.
The only people might look are maybe trying to fix a problem with those same circuits and Many of those have seen wire switch in 20+ years of PFF and others publishing same data to see if the switch has been done or not. Otherwise no-one will look.

"and that it is overly complicated." yet can splice I-switch wire to the bulbs to fix the GM F'up to have Temp light to have Bulb Test so can see bulb works like a few others when you turn the Key to Bulb Test or Start. And You do that exactly where w/o pulling the dash apart? As soon as you pull dash cover/trim... at that point is so close do the same work. (Bulb Test and Start are two different positions for the I'switch w/ Bulb Test overlapping Start. Very Slowly turn the key to see this happen in most old GM cars.)
In Fact, I'switch terminals are same as many others and if you have spare pigtails can have same results w/o cutting but need to lower the Steering column to access the I-switch plug so almost no-one will bother.

Both or even just cutting 1 wire will make Fiero wiring Not to match FSM et al and often harder time to trace to see if that causes problems. More people including many nube DIYers see any non OE wiring and Cut Factory wiring very easy and will think that is bad right out of the box and for good reason because Most aftermarket things are installed very poorly and cause major problems to fires.

About to only danger following above PDF is most plugs in engine bay are very cooked and often fall apart trying to remove terminals.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

fierorestore85 SEP 30, 03:32 PM
Thank you everyone for your replies!
I'll try out the repair guide from the PDF that Camel linked to and see if it works out. I appreciate the help! I'll update on how that went!
olejoedad SEP 30, 07:05 PM

quote
Originally posted by theogre:

Yes, Can cut the wire to I-switch wire to the gauge...

"The only problems with it are the engine wiring harness wire colors no longer match the FSM wiring diagrams, which may lead to confusion to someone down the road..."
Right. Not.
Nearly no-one will notice wire color change if you switch wires per above PDF etc. Including nearly all "pros" including 99.99+% of GM dealer service shops and ASE holders hired by Pepboys and others.
The only people might look are maybe trying to fix a problem with those same circuits and Many of those have seen wire switch in 20+ years of PFF and others publishing same data to see if the switch has been done or not. Otherwise no-one will look.

"and that it is overly complicated." yet can splice I-switch wire to the bulbs to fix the GM F'up to have Temp light to have Bulb Test so can see bulb works like a few others when you turn the Key to Bulb Test or Start. And You do that exactly where w/o pulling the dash apart? As soon as you pull dash cover/trim... at that point is so close do the same work. (Bulb Test and Start are two different positions for the I'switch w/ Bulb Test overlapping Start. Very Slowly turn the key to see this happen in most old GM cars.)
In Fact, I'switch terminals are same as many others and if you have spare pigtails can have same results w/o cutting but need to lower the Steering column to access the I-switch plug so almost no-one will bother.

Both or even just cutting 1 wire will make Fiero wiring Not to match FSM et al and often harder time to trace to see if that causes problems. More people including many nube DIYers see any non OE wiring and Cut Factory wiring very easy and will think that is bad right out of the box and for good reason because Most aftermarket things are installed very poorly and cause major problems to fires.

About to only danger following above PDF is most plugs in engine bay are very cooked and often fall apart trying to remove terminals.




Thanks for your long winded reply.

I suppose you know that the wires attached to the ignition switch only supply a ground to the circuit during BULB TEST.

All you need to do is drop the lower trim piece under the steering wheel to perform the change I outlined in my first post, unless you want the HOT lamp to light during BULB TEST.

[This message has been edited by olejoedad (edited 09-30-2019).]

Kevin87FieroGT OCT 02, 08:50 PM

quote
Originally posted by fierorestore85:

Thank you everyone for your replies!
I'll try out the repair guide from the PDF that Camel linked to and see if it works out. I appreciate the help! I'll update on how that went!



That’s what I did. It worked fine.
Spoon OCT 02, 11:17 PM
Wait, don't clap yet. I did the "Fiero Sails" mod on my 86 2.8 a long time ago and it worked great. After recently doing the 3800SC swap the temp needle is pegging again. I swapped back the 2 wires behind the dash pod 11&13 and it made no difference. I thought about swapping back the wires on the 3800 temp sensor but my 3800SC configuration has a lot of stuff crowding that area and I'd hate to do it for no results. so here I am.

What went wrong? I can't be the only one, right?

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut