Non-Deluxe Gauges to Deluxe swapover?

[GMCNUT]

I'm sure this question has been asked by someone before, but I am at the point where I need to know - so my current build is a short fleet BBW 63 Chevy and it came like most with the plain idiot light guage cluster. I have a nice factory tach deluxe cluster and associated cluster wiring, but if I simply unplug the non-deluxe and plug in the deluxe, will everything work assuming I've also swapped the engine harness to a deluxe? Wondering if you have to have the whole fuse block and inside wiring for a deluxe cluster to work - anyone know?

[ray_mcavoy]

There are 5 wiring harnesses that need to be changed or modified when swapping from warning lights to a gauge cluster.

(1) The small harness that's on the back of the cluster is significantly different between warning lights & gauges. However, these harnesses are often left attached to the back of the gauge clusters so you may already have this one.

(2) The tachometer has it's own separate harness. Again, you'll need to get one of these unless one was already included with your gauge/tach cluster.

Note: The 60-62 factory tachometers used an external sender. While the 63-66 tachs have all of the electronics located inside the tach assembly. Externally, they both look very similar but the wiring harnesses & connections are significantly different.

(3) The cab harness (which includes the fuse box) has a few minor changes. Most important is the re-routing of a couple wires to work with the "BATT" gauge (ammeter) instead of a "GEN" light.

The 63 cab harness used with warning lights has a brown wire for the "GEN" light that shares a common terminal on the LH bulkhead connector with the 10Ω resistance wire (brown with white stripe) that comes from the ignition switch. And there is an unused cavity in the LH bulkhead connector.

While the 63 cab harness used with gauges has a red (instead of brown) wire for one leg of the ammeter circuit. It follows the same route as the brown "GEN" light wire and can be re-purposed as such. However, you need to cut the resistance wire (brown w/white stripe) from the shared terminal (leaving the brown wire alone), crimp a new terminal onto the resistance wire, and insert it into the formerly unused cavity in the bulkhead connector.

The cab harness used with warning lights also has a leg of the "HOT" light circuit going to a grounding contact on the ignition switch to perform a "bulb check" when cranking the engine. If that connection is left in place when the "HOT" light wire is re-purposed for the temp gauge sender, it will cause the temp gauge to jump to the hot side when cranking the engine. That won't do any harm, but disconnecting that wire from the ignition switch "GRD" terminal will prevent it from happening.

(4) The engine harness used with gauges has a black wire (with an inline 3A fuse) that connects to the starter solenoid BAT stud. This forms one leg of the ammeter (BATT gauge) wiring. And it has a different connector on the dark green wire for the temp sender.

(5) The front light / alternator harness used with gauges has the brown wire from the #4 regulator terminal hooked to a different cavity in the LH bulkhead connector. This joins it to the 10Ω resistance wire in the cab harness. And it contains an additional red wire that connects to the junction block on the horn relay for the other leg of the ammeter. Although not factory, I highly recommend adding a 3A inline fuse to this wire as well.

In addition to the wiring changes, you'll also have to swap out the temp sending unit for one that works with the gauge instead of warning lights. And add steel or copper tubing for the mechanical oil pressure gauge.

[GMCNUT]

Wow - Ray you really know your stuff here. I appreciate these detailed answers. I really need to do some work on my under-dash harness it sounds like, so I will plan to remove it and re-work according to the above and re-use then. Sounds like I need to source a deluxe guage alternator harness, so will look and see if those are reproduced like the engine harness I already bought. Thank you for the great help - I may send you a question or two if I get stuck...thanks again Steve

[LostMy65]

I think someone posted a mod to change the ammeter to a voltage meter.
I'll see if I can find it.
The ammeter gauge I've read is pretty prone to electrical fires. In my thread I write about one I had back in 85 because of the ammeter.

[ray_mcavoy]

You're welcome!

If your truck's existing front light / alternator harness is still in good condition, you could modify it to work with the gauges by re-locating the brown wire to the appropriate cavity in the bulkhead connector and adding the red wire for the ammeter (with an inline fuse) to the junction block on the horn relay.

But if it's not in good condition, reproductions of the 63 gauge type front light / alternator harnesses are available from either M&H or AAW in their "Factory Fit" series. They're typically listed in the catalogs as a "forward lamp harness" or "front light harness".

It looks like M&H and AAW are both offering 3 versions of these harnesses that will work with gauges. One is for use with the stock type externally regulated alternator. The other 2 are pre-modified for use with newer SI series internally regulated alternators (one is for driver side mount and the other for pass side mount).

The cab harness (often called a dash harness) is also available as a reproduction. But if your existing cab/dash harness is in good condition, it is fairly simple to modify as I posted above. I forgot to mention it earlier, but the terminal you'll need to crimp onto the resistance wire is a Packard/Delphi 56 series female terminal. They're available from a number of sources including many local auto parts stores.

[LostMy65]

Here's one thread with a link to another.
The one I'm looking for has it looking stock.
http://Www.67-72chevytrucks.com/vboa...mmeter+voltage

[ray_mcavoy]

Originally Posted by LostMy65

The ammeter gauge I've read is pretty prone to electrical fires.

Yes, the 64 - 66 ammeter wiring wasn't the safest because it didn't have any fuses. Some of the earlier years did in fact have a 3A inline fuse from the factory but it was only in one leg of the ammeter circuit. I don't know why GM left out the fuses for 64-66.

In any case, simply adding a couple of 3 or 4A inline fuses (one in each leg of the ammeter circuit ... just like GM did with the 67-72 and 73-75 trucks) will make the stock ammeter just as safe as a voltmeter.

[LostMy65]

Knowing that, I might hook mine up again.
Thanks

[GMCNUT]

Ray, I might need your input again here - I found two sources for new 1963 Alternator harnesses for trucks w/ guages - BUT - one is less than 1/2 the price of the other - Eckler's wants 92.99 where Classic Parts only wants like 39.99 for what is being shown and said to be the same harness. Wondering what you would recommend based on what you can tell of these - can't say for sure if they are both the same in terms of having the exact wires where they need to be, etc, but both do say 63 Chevy Truck with guages....thoughts?

http://www.classicparts.com/1963-66-...tinfo/52-230/#

http://www.ecklerstrucks.com/chevy-t...1963-1966.html

[ray_mcavoy]

Originally Posted by GMCNUT

Wondering what you would recommend based on what you can tell of these - can't say for sure if they are both the same in terms of having the exact wires where they need to be, etc, but both do say 63 Chevy Truck with guages....thoughts?

Based on the fitment listings, it looks like either one of those harnesses would be suitable for your application.

It's hard to judge the quality of a wiring harness based on the photos. However, I did notice the Classic Parts description says: "Uses modern PVC coated copper wiring in the correct color codes with original connectors." The trouble with that is most PVC insulation is only good for temperatures up to 80°C (176°F). I'd be leery of using that type of insulation for engine compartment wiring. Granted, the front light / alternator harness is not routed very close to the engine. But I still think wire with a cross linked polyethylene insulation (such as type SXL ... good to 125°C / 257°F) would be a better choice. And that's probably what accounts for a good portion of the price difference. I also noticed that the connectors on the Classic Parts harness aren't all the original style as the description claims. It looks like they're using generic ring terminals (with the yellow & blue insulated barrels) instead of OE type un-insulated ring terminals on the ground wires. But that's not a real big deal unless you're doing a 100% stock restoration.

I don't know who Eckler's is using as their wiring harness provider but their price looks more in line with harnesses from AAW, M&H, or Lectric Limited. Assuming they're made by one of those 3 companies, I'd recommend them over the lower cost Classic Parts harness.

[GMCNUT]

Thank you Ray - another big help. I am going to also try and source a perfect uncut-on original alternator harness too - I may opt to install a nice clean original over aftermarket - we'll see