How To Repair Stock Up Amphere Gauge

AMP gauges at the dash are troublesome.

They should be past-passed, and then install a VOLT gauge.

by Mark Hamilton

THE Problem

The antiquated AMP estimate system has reduced more Dodge owners to pedestrian condition than whatever other kind!

And (wire) �last disease� at firewall connectors has likewise been a major trouble.

(Chrysler Corp. stayed with the old AMP judge organization long afterward other automakers switched to VOLT gauges, and Dodge trucks used the AMP gauge more recently than others, so we have used a Contrivance truck as a model for this project.)

Dodge is not the only brand with concerns near AMP gauge systems, early on FORD Broncos, International Spotter, and many old cars and trucks used the AMP gauge system besides. But when the electrical system will be upward-graded with more powerful alternators and more accessories, the AMP gauge should exist removed, and the �chief power organisation� should exist modified.

With normal simply frequent use, near of these Dodge trucks will take electric wiring bug. The first to fail were often the trucks equipped with factory air conditioning. The air conditioning system adds a significant electrical load. And the �air� gets used in hot summer weather when heat will increase resistance at connections. The boosted current flow when using the air conditioning and increased resistance with estrus will break downwards the weak areas more than quickly. With sufficient use, the non-air equipped trucks will also have electrical problems stemming from the aforementioned crusade.

Typical Contrivance electrical issues result from a very antiquated power distribution organisation. The main source of power for the Dodge electrical system is based upon an old blueprint AMP estimate at the dash and related wiring system. Information technology�south a system that worked okay with a very pocket-sized electrical organisation on Model A Fords way back in the late 1920�s. But the old AMP-gauge-at-the-dash system is not reliable with increased current loads of the more modern electrical system.

Compounding the situation, the wiring system for the AMP gauge actually became weaker than information technology was over fifty years earlier. Assembly line labor was non and so expensive in early years of the motorcar. Affordable labor could consistently connect wires with �ring terminals� at screws or studs with nuts�resulting with reliable (low resistance) connections. With increased labor price mandating fast moving associates lines, and many more than wiring circuits to install, �click together� connections have been widely used since dorsum in the 1950�due south. And past the 1960�s, even the AMP guess (heavy current load circuit) was routed through a �click together� connection. The least reliable of �click together� connections for a heavy current load circuit is the male/female flat bract terminal blueprint. And it happens that Dodge was built with this terminal design, even at the main power commitment circuit.

In summary, the AMP gauge and related wiring establish in Dodge trucks of the sixties and seventies menstruation was built with a recipe for failure. A 70amp alternator supporting powerful electric accessories was typical equipment by 1979, and the load was too much for the method of wiring structure used. Naturally, it�south a system that often reduced Dodge owners to pedestrian status.

This feature clearly explains the shortcomings of using the sometime, traditional, AMP judge at the nuance. And largely because of the excursion design shortcomings, the best choice of gauge to monitor the electrical arrangement is a �VOLT� rather than AMP guess. A proficient caption of the AMP vs. VOLT approximate may exist found at www.autometer.com in the Tech Tips / FAQ section of the web sight.

THE HISTORY

In some ways, the Chrysler Corporation was pretty far advanced where electrical systems were concerned. (Chrysler gave usa the Dodge, Plymouth and Chrysler line, and nowadays they all may exist referred to as MOPAR.) Back in the early �60�southward, MOPAR was the first to give us alternators rather than the older engineering science generators�Indeed the improvement was cracking. GM followed, and then Ford finally installed alternators as �standard equipment� on �65 models.

1964 year model Chrysler products showed up with �Fusible Link wires� for reliable short-circuit protection of the main ability excursion from the battery to the electrical system. Chevy didn�t use Fusible Link wires until �66 models.

And Ford didn�t utilize Fusible Links until some years afterwards GM.

Chrysler/Dodge/Plymouth introduced a very good electronic ignition organisation with 1971 models. Ford introduced a somewhat less reliable electronic ignition with only some of their �74 models. And GM gave us a very good electronic ignition with �75 models.

In spite of being the first to requite us �break through� technology with components, it seems that the �Contrivance BOYS� were reluctant to depart from a very blowsy wiring arrangement. The old, traditional, �total current load type� AMP-GAUGE-AT-THE-Dash and related wiring system was still in apply with �79 Dodge trucks. The AMP gauge circuit wiring had to evangelize electric current used by the entire electrical system, plus handle current to recharge the battery. The problem was that current load and the alternator output rating was a large amount by the end of the �70�s. Alternators with about a 70 amp bachelor output were standard with air-conditioned models. And a weak final pattern was used where the AMP judge wiring passed through the firewall. The large demand for electrical electric current often resulted with failures in the lengthy AMP gauge circuit, even in vehicles that were relatively new.

The original AMP gauge system served as the main power distribution organisation. This circuit is the power source for the entire electrical system. (see diagram A)

Amp gauges at the nuance were standard equipment with Model A Fords, back in the belatedly 1920�southward. And the fifteen amp capacity gauge at the dash worked fine with minimal electrical systems of that menses. Electric current output from the small Model A generators was not even sufficient to support sealed axle headlights. (The one-time Model A was equipped with a small low-cal bulb backed up by a large reflector in the headlight assembly.) The Model A only had 1 tail/brake lite at the rear, a simple ignition organization and a modest battery about completed the electric arrangement. Such a small corporeality of electrical current flow through expert connections at the AMP gauge wiring was no problem with the Model A Ford. And with electric current output limited by a cutout relay on the generator, the AMP estimate could handle the small bombardment accuse rate. But as electrical systems became more than powerful, Ford discontinued the old AMP judge system long earlier the �70�southward.

GM also up-graded their arrangement long before the Dodge Boys. When GM introduced the alternator with �63 models, it was controlled by a more than complicated but more efficient voltage regulator system. And the new GM organisation could support a warning light at the dash. The warning light was oft standard equipment and the gauge was an option. GM vehicles built with the gauge option also had a more modernistic design of AMP approximate at the nuance. The newer AMP gauge was a remote shunt type design�a length of the battery charging wire in the under-hood harness served as the shunt. The dash guess and related wiring no longer handled heavy current load. Aforementioned with Ford in �65 and newer model cars�the Ford organisation could work with a warning light at the dash, and cars that came dash gauges had a remote shunt type amp judge.

The Dodge alternator/voltage regulator system had no provision to operate a warning light. And Dodge (trucks) stuck with the former blowsy �full load blazon� AMP gauge design, at least into the late 1980 models. As is typical of Dodge trucks that were used a lot, the AMP gauge in this �76 Dodge was burned out. The plastic mounting area behind the dash is completely melted, and the lens and plastic trim is shriveled too. (This estimate is included in Diagram A.)

Amperage is a measure of electric current menstruum, and all of the current used to recharge the battery was routed through this gauge�which caused the gauge to display the bombardment charge rate. Both the alternator and the battery were mounted up front, under the hood. And the AMP gauge was at the dash. It was an arrangement resulting with a very long wire circuit charging the battery.

Big amounts of current flow through the AMP gauge will generate some heat besides. The plastic cover at this estimate was only distorted by estrus�only some Dodges have sizable holes burned in the dash where the AMP gauge used to be. Apparently, the shunt in the gauge has a sufficient corporeality of resistance to generate a damaging amount of heat with battery charging current flow.

A previous owner had replaced the terminals at the back of the AMP gauge, then did a weak past-pass of the gauge by taping the ii wire terminals together. (No doubt an endeavor to go the old Contrivance upwards and running.) It�s fairly common to observe the wires disconnected from the gauge, and a machine screw and nut clamping the terminals together, and finished by wrapping the spiral and terminals with tape.

The AMP gauge wiring passed through the �firewall bulkhead connector,� where standard, .250 inch wide, male/female apartment blade connectors were used. (This connection is shown in Diagram A.) These terminals were reliable with circuits of much less current flow, as with plough signal, clearance lights, and temp or fuel gauges. But the design was certainly not up to the task of handling the entire alternator output. This was a problem spot in the AMP judge arrangement that often made Dodge owners walk.

Pointer A in the photograph at the left points out a melted crenel in the plastic connector body, where a instance of �terminal meltdown� occurred. This connection served as a pass-through for the primary wire from the alternator to the nuance area. When driving, the entire electrical system current load volition pass through this connector. (Also seen in Diagram A.) Ignition, lighting, heater fan, accessories, and electrical power in general flows through the connector. The wire color code is black at this circuit, and this model was equipped with 10 gauge wire. (Many before models had only a 12 gauge blackness wire.)

Arrow B points out the cerise, ten estimate, battery charging wire.

Subsequently removing the connector with the ruddy x estimate battery charging wire, a close inspection revealed that this side of the AMP gauge circuit was too suffering from a case of �terminal disease.� (Run across pointer in photograph at the left. This is the terminal used past the 10 gauge cerise wire at pointer �B,� above.))

The plastic connector body surrounding the female flat blade terminal is beginning to melt away. And severe oxidation of the final itself is evidence that this terminal has been glowing hot. Find that the other terminals in the connector trunk are even so in good condition. The rusty appearance of this terminal is typical of wire terminals that have been hot while handling large amounts of current flow. (If moisture had acquired the oxidation, all the terminals would take been corroded.)

We have opened part of the dash wire harness, to evidence the factory �welded splice� where wires branch off to the ignition switch, light switch, and the fuse box. (This splice is shown in Diagram A.) The �welded splice� is insulated past a factory installed, sticky cloth tape.

The original tape has been removed for this photograph to expose the �welded spice.�

Pressure and rut fused the copper wire strands together when making the splice. The method seems to be reliable, equally in thirty years of workshop experience the author has never seen a failure with this splice. When electrical ability loss occurs, this is certainly not the first place to look for the problem.