Swapping gauge insert

[bestchevyfan]

My 1987 truck has idiot lites and i want to change to gauges with a clock. What do i need to do ??

[Nick_R_23]

You’re in for some wiring. You’ll need to replace the oil pressure and temp switches with sending units, the under dash and engine bay wiring is different, and the entire gauge cluster will need to be changed.

[evan]

Originally Posted by Nick_R_23

You’re in for some wiring. You’ll need to replace the oil pressure and temp switches with sending units, the under dash and engine bay wiring is different, and the entire gauge cluster will need to be changed.

That's not what I was hoping to hear. I found a set of gauges to replace my idiot light gauges and was hoping it would be simpler.

[TrailerTrash]

It is not simple at all. I am sure many of us had the same idea at one point or another but there is a good bit to it as said above.

The idiot lights arent individual cups that can be removed to make room for small guages. It's all one large assembly that houses all the gauges or gauges+idiot lights. You would have to cut stuff up to make room then run all your own wiring for new gauges then mount everything and make it look good.

Not trying to scare you away from the project, but it wouldnt be easy

[evan]

Originally Posted by TrailerTrash

It is not simple at all. I am sure many of us had the same idea at one point or another but there is a good bit to it as said above.

The idiot lights arent individual cups that can be removed to make room for small guages. It's all one large assembly that houses all the gauges or gauges+idiot lights. You would have to cut stuff up to make room then run all your own wiring for new gauges then mount everything and make it look good.

Not trying to scare you away from the project, but it wouldnt be easy

Just to clarify, I was talking about swapping a stock gauge cluster that has needle gauges in place of the stock gauge cluster that has idiot lights. Is that what you're talking about?

[Nick_R_23]

Yes. The gauge cluster itself (housing, lens, circuit board) is different between the two versions, the entire unit needs to be replaced. Along with the interior and engine bay harnesses, although it’s not impossible to rewire them for the gauge style clusters. Lastly, the actual sensors on the engine for the gauges are different - idiot lights used switches (on/off at a certain spec), and gauges used sending units. The sending units should physically fit where the switches were, but the connectors and wiring is usually different.

It’s definitely not impossible, but it will take a little effort and ability to compare wiring differences between both styles.

[blazer2007]

If you don,t want it factory wiring I used the idiot light curcuit board and just wired the temp and oil gauges seperate to gauge sending units my clock didn,t work so I never did that wiring but left the clock in anyway. If you want to re-pin the the harness I think this the thread. http://67-72chevytrucks.com/vboard/s...d.php?t=452340

[wazzabie]

I thought the gauge clusters clusters were swappable with dependency upon certain years. Maybe that is only if you are adding a tach cluster to an existing gauge cluster with no tach. I have a 78 gauge cluster that I'm swaping to a tach cluster. Other then adding the tach wire I've been told it is plug and play.

[hatzie]

It's not oogie boogie. It's also not difficult.
You can swap 1973-80 warning lamp clusters for 1978-80 gauge clusters with some minimal work. Don't use the 73-77 clusters for this.
1973-75 gauge clusters have ammeters and capillary tube oil pressure gauges.
The ammeter was replaced with a Volt gauge in 1976.
The capillary tube gauge was superceded by an electric gauge in mid 1977.

The gauge fonts and colors changed in 1981.

The wiring from the engine bay will work for gauge senders or lamp switches.
The instrument panel plug will need to be re-pinned.
The temp and oil pressure switches will need to be replaced with gauge senders.

Pinout charts are in this thread. http://67-72chevytrucks.com/vboard/s...d.php?t=456877
Year specific GM wiring diagrams are in the manuals thread in my signature.

[wazzabie]

Is there any advantage to use the capillary tube gauge vs the electric temp gauge?

[evan]

Originally Posted by hatzie

It's not oogie boogie. It's also not difficult.
You can swap 1973-80 warning lamp clusters for 1978-80 gauge clusters with some minimal work. Don't use the 73-77 clusters for this.
1973-75 gauge clusters have ammeters and capillary tube oil pressure gauges.
The ammeter was replaced with a Volt gauge in 1976.
The capillary tube gauge was superceded by an electric gauge in mid 1977.

The gauge fonts and colors changed in 1981.

The wiring from the engine bay will work for gauge senders or lamp switches.
The instrument panel plug will need to be re-pinned.
The temp and oil pressure switches will need to be replaced with gauge senders.

Pinout charts are in this thread. http://67-72chevytrucks.com/vboard/s...d.php?t=456877
Year specific GM wiring diagrams are in the manuals thread in my signature.

That's very helpful. Thanks.

[hatzie]

Originally Posted by wazzabie

Is there any advantage to use the capillary tube gauge vs the electric temp gauge?

It's the oil pressure gauge that uses a copper capillary tube with compression fittings on the engine and the gauge.
The temp gauge was always electric. The temp sender was a nailhead thermistor sender through 1979 1980ish and then various flavors of thermistor senders with differing resistance curves. The less than pleasant reality is that the replacement nailhead senders and probably the others have a different thermistor semiconductor brew than the originals so I'd keep your old ones as long as they work.
IMHO the negatives of the old oil pressure gauge outweigh the positive.

[bestchevyfan]

To change it out === i will need a dash cluster w/ gauges == i have it . [2] wiring harness for under dash. [3] wiring harness for under hood [engine] [4] send units for under hood . Is this all i will need ??????? Thanks,buddy

[TKCR]

Originally Posted by hatzie

It's not oogie boogie. It's also not difficult.
You can swap 1973-80 warning lamp clusters for 1978-80 gauge clusters with some minimal work. Don't use the 73-77 clusters for this.
1973-75 gauge clusters have ammeters and capillary tube oil pressure gauges.
The ammeter was replaced with a Volt gauge in 1976.
The capillary tube gauge was superceded by an electric gauge in mid 1977.

The gauge fonts and colors changed in 1981.

The wiring from the engine bay will work for gauge senders or lamp switches.
The instrument panel plug will need to be re-pinned.
The temp and oil pressure switches will need to be replaced with gauge senders.

Pinout charts are in this thread. http://67-72chevytrucks.com/vboard/s...d.php?t=456877
Year specific GM wiring diagrams are in the manuals thread in my signature.

You sure are a big asset to this board! Your knowledge & help is greatly appreciated.

[Factory Guy]

American Autowire has the dash gauge harness you might be in need of

https://www.americanautowire.com/sho...harness-105011