SR5 Gauge
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Last Update: October 29, 2005
For many years, Toyota saw fit to include two different gauge packages on it's trucks.   The standard cluster would include a speedometer, gas
gauge and engine temp gauge, and that was it.     The earliest Toyota trucks through 1983 would have optional gauges for oil pressure and volt
meter in the dashboard, independent of the speedometer gauge cluster.    Beginning in 1984, when Toyota redesigned the gauge cluster, they
included all of the gauges in a single pod just a head of the driver.   On SR5 trucks, Toyota included a tachometer, oil pressure gauge and volt
meter in addition to the standard speedometer and temperature gauge.

What many may not know is that these gauge clusters are actually interchangeable.    An SR5 gauge cluster can be swapped into a truck that
came stock with the standard gauge cluster.     On 1984-1988 trucks and 4Runners,  the trucks are largely prewired for the SR5 cluster, but in
some cases, additional wiring and relays may be required.

Since my truck is a 1989 model, this article will focus on the 1989-1995 Toyota pick-up and 1990-1995 4Runner cluster swap.    When changing
out the clusters, a number of considerations need to be undertaken.

First, when searching for an SR5 cluster, you need to pay attention to what engine you have and what model year your truck is.   For the tachometer
to work properly, you should source the SR5 cluster from a truck with the same engine.  For example, if you have a 22R or 22RE truck, you should
get cluster that came with a 22R/RE.  Same with the V-6.

The second thing to consider is type of speedometer you have.   From the late 1970s through approximately 1992, Toyota used a cable operated
speedometer that operated via a cable and gear system hooked directly to the transfer case.   Sometime, approximately mid-year 1992, Toyota
introduced the electronic speedometer.  Instead being mechanical actuated, an electric motor inside the speedometer used a sensor located on
the transfer case.  Both used the same type of dial speedometer on the outside, but the insides are different and the two systems are not
compatable.  So, if you have a 1989-1992 truck, you'll likely need a speedometer from that range.   Later model trucks will need later model
speedometers.   1992 and 1993 trucks could vary, since it's not really clear when the change took place, so the gauge cluster will need to be
examined to see what type it is.

For 1989-1995 trucks, the trucks are prewired for the gauge cluster, so once the SR5 cluster is obtained, it's really just matter of unbolting and
unplugging the old cluster, and plugging the new one in.

The final and most important modification is to swap out the oil pressure senders.  The reason why this is the most important is because it's often
the most overlooked thing and if not done before the new cluster is installed, the oil pressure gauge can be burned out.  More on this below.
If you don't yet have a new gauge oil pressure sending unit or don't yet want to install it, then you should first unplug the wire from the idiot oil
pressure sender before turning on the ignition and using the new gauge cluster.
This is my current gauge cluster set up.    The cluster I obtained was from a wrecking yard.  It came out of a 1990 4Runner, but I wasn't sure what engine.  Fortunately, I
got lucky.   The tach worked just fine.   What didn't work fine was the oil pressure gauge.  But that was my fault.  I burned it out when I plugged in the cluster, before
removing the stock idiot light sensor.

I initially purchased new gauge and a new sending unit.   However, it never worked that well.   In the end, I discarded the stock oil pressure gauge all together and went
with a much better set up.  In place of the stock gauge, I mounted an custom low oil pressure warning light.  A new VDO oil pressure, which is far more reliable and
accurate was mounted on the dash.  See below for how the sensors were hooked up.
This is the gauge oil pressure sending unit.  Cost is about $50 from the dealer.   It's much larger than the stock idiot light and is harder to install, since you have to a
wrench around the big part of the sensor.   It's a variable resister ground which controls how much current is allowed to flow through the gauge.  Unlike the idiot sensor
which is a simple on/off switch, turning on, when the oil pressure is anything less than 4 psi and off when it climbs above that.
The main oil pressure sensor is located directly below the oil filter.   What a lot of people don't know is that on 22R and 22Re engines, there is a second oil pressure port
that is not used.  It's located inside the engine mount, directly to the right of the primary oil  pressure sensor.   The second port is normally closed with a bolt.  The reason
for it's existence is because the engine mounts are actually designed to be mounted in two separate locations, depending on the vehicle the engine is mounted in.   In
either position, the mount covers on oil pressure port or the other, so the opposite port is used for the stock sensor.   However, even with the engine mount covering this
port, it is still accessible.    The area is small and hard to get too, so the larger gauge sensor will not fit.  However, the small idiot light sensor fits perfectly.  This second
port is what I used to power my custom idiot light.  The primary port is used to power the aftermarket VDO oil pressure gauge.
These are the two oil pressure gauges that I had.  The one on the left is the stock gauge that came with the cluster that I purchased out of a 1990 4Runner.  This is the
gauge that burned out.  The gauge on the right is the one that purchased from a Toyota dealer new for about $50.  What I found was that it never worked properly.  In
fact, from the factory, it wasn't even set to the zero mark.   In close examination, I found the construction of both gauges to be similar, but different in  a few msall ways.   
The part number of each gauge was also slightly different, but I suspect the new one was simply an updated version.  

As you can see, the Toyota oil pressure gauge is an extreme primitive design.  In fact, it's hardly worth having.   It's design makes it difficult, if not impossible to calibrate
and it's not hard to understand why Toyota never printed numbers on the fact.  In fact, two Toyota oil pressures gauges are very likely to give different readings with the
exact same oil pressure.
The two photos on the left show the gauge that I burned out.  The wire got hot and melted, when the gauge remained hooked up to the stock idiot light sensor, while I
turned on the ignition, but not the engine.   With the engine not running, but the gauge being powered, full current flowed through the gauge, which it was not designed
to handle.   In addition to this, the metal rod which bends when heated by the wire, had bent all the way to one side, distorting it to the point that the gauge would not
read accurately, even when the wire was repaired.

The photo on the right shows the brand new gauge internals.    My conclusion is that the factory oil pressure gauge is worthless and I highly recommend discarding it for
a more accurate aftermarket gauge.  Interestingly, the other gauges, such as the temperature and gas gauge are of a more common, coil wire design and are more
reliable and accurate.
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