Chevy Astro and GMC Safari Forum banner

My 'New 91 Astro" has issues

1K views 4 replies 3 participants last post by  91astroluv 
#1 ·
Hi All, I am new to this site as I have just bought a 1991 Astro Cargo van to use for my work and although it runs good I have a few problems. 1) The speedometer and odometer do not work
2) The oil pressure gauge stays on H when the engine is running
3) The switch for the blower is not working, it just moves back and forth like it's not connected to anything
4) The red light that says Brake blinks on and off as I drive along :ty:
Any advice would be greatly appreciated from this great site.
Thanks, Frank
 
#5 ·
x2^^^^

Seeing you are removing the gauges/ cluster go a head and disconnect the harness from the cluster and the string attached to the steering column
(it's how your cluster displays the gear you are in (PRNDL) commonly reffered to as the "prindle". Now look at the back of the cluster. Notice anything
wrong with the film containing the circuit board? Is it scorched, broken, or cracked? maybe its time for a new cluster?

****Does your headlight switch and dimmer function properly? These are two seperate switches behind the facing-they look like one on the outside.
They draw a large amount of voltage! I have seen several Astros with these switches burnt up affecting the harness because those wires get red hot when shorted. This causes other smaller wiring to melt. I have seen a couple of burnt up astros where you can see clearly the light switch was the culprit. I fortunately recieved mine with the head light switch disconnected and connected to a sloenoid to run full time. The dimmer switch is still connected and functions. Less of a hazard.

If the fuses are blown, replace them, if it/they blow again then something is causing them to blow. NEVER NEVER EVER- Jump the connetions where
the fuses go!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! you will ask the short to do what a short does SHORT and BURN and you got a potential fire going.
You will also send the sensors, switches and computer voltafe they are not designed to recieve and short those out as well. Replacing the fuses and them blowing means the fuses are doing their job-stopping juice to flow to the short and protect the other side of the circuit.

I would think that the next step would be is to check the temp sensor and oil pressure sensor.

A visual inspection to confirm they are connected clean and functioning. If you see issues there remember if the cluster/ gauges are ok
they are displaying the input they are recieving. There are only two ways it can receive bad input signal

1.) Problems with the sensor(s) them selves

2.) bad, loose or shorted wiring, blown fuses all which affect the voltage the gauge(S) need to operate CORRECTLY.

As for the heater switch:
Confirm that the heater/ climate box cable is connected. That is the only thing that will
give you that "connected to something feeling".

There are two screws under the gray facing/ trim surrounding the switch, remove those and gently pry the trim out
the switch will more than likely come out with it.

You will feel some resistance because there are two plugs and a cable attached to the back of it. The plugs are at the top
and the cable is at the bottom. The cable is secured by a bright RED plastic anchor/ connector.

Should these items be securely in place I would tend to think you MAY have an issue with in your harness.
The harness for the electrical plugs on the heater switch run from the Right/ driver's side (fuse box) to the center of the dash.

As for the brake light going on and off that too is a switch an odd looking little creature too! The brake light swtich is located in the same
area as the heater switch (right of steering column) but it is under the dash- look above the gas pedal area, you will see two white about as round as
a roll of spree candy and about 4 inches long with electrical wires comming out of them. Chec to see that your break pedal is making contack with it, that they are connected. Becarefull if removing it to check it out they are fragile and again, odd not your average looking switch.

Coincedently, they are tucked in the same place/ path as the wires for the dash gauges/ cluster. If you have a fused section
that may be why? The brake light, oil pressure, temp gauge AND the heater switch is affected. You see there are three diffrent section suffering
here and on the same path- the harness. The engine compartment oil/temp sensors, the dash area being the gauges and the heatier switch AND the brake section/ brake light going on and off.

Once you remove the cluster/gauges and see the plug you COULD test the connector to see that the cluster is getting the right signal. However; another member is gonna have to guide you with this endeavor as using a volt meter is not my strong point. A buddy and a 6 pack for him is how I read voltage. lol

I have a 1990 astro and have been living at the J YARD for the past two weeks on a shopping spree. The shopping spree came with the condition that I removed the part(s) I wanted. So, I stripped apart 4 diffrent astros and a safari, all second generation. I am quite familiar with the locations of everything.

I am going to hazard a guess here I believe your issue is going to be somewhere between the fuse box and the dash area. It seems more likely to me because their are diffrent fuses for the problem area(s) (fuse box is labeled). For all of the areas to be afflicted at once they could be afflicted at the same spot/ location. Thus causing eroneous display result(s) and no heater function(s).

Now the BAD NEWS. In order to inspect/ test out your harness to these items --You have to remove the dash board and the heater ducts because the harness is tucked between the two.

But before we get into dash removal lets follow the diagonistics first and do the visual inspections and testing first i.e. replacing blown fuses etc.

I would also advise you to spend the $20.00 on a haynes or chilton repair manual. I have them and they are a good reference and informative source.

Happy hunting, Hope this helps
Trip
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top