Printer Friendly Forum Posts - 1997 chevy truck power locks

If the truck came equipped with keyless entry than relays are not required and install as 3 wire positive pulse.
If the truck did not come equipped with keyless entry than relays will be required and install as 5 wire reverse rest at ground.

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This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

Thank you for the quick response. I just bought the truck used and didn't receive a keyless fob. I pulled the door switch off and there are more than three wires. There was about 7 or 8. I am assuming itst he 5 wire and additional wires for illumination of the switches. This leads me to a couple of quick quesitons on wiring of the relays.

Does it matter which switch I wire these from (driver or pass)?

Is it acceptable to use the 12V that is present at the switch to power the relays?

Is there a preferred method of mounting the relays in the door, or run additional wire to the kick panel?

Any help is appreciated. Thank you.

dkeys,
No that is not what I mean, you do not need to access the wires at the switch. Although, 3 and 5 wires do refer to the number of wires at the switch, for this vehicle you do not need to go there.
The wires you will need is in the drivers kick panel.

Lock = Light Blue
Unlock = White

Depending on the system the is being installed, you may or may not need relays to operate the locks. If the system have on-board relays, you will not need any additional relays for either configuration. If the system only has outputs, than you need to determine if they are negative outputs or flip-flop (goes + or - depending on lock or unlock signal from system). If they are flip-flop, you will need two diodes, one to each output, with the bands away from the keyless entry unit, if your vehicle original came with keyless entry FROM THE FACTORY. If they are negative only, you will need relays, see attached links for assistance. Check you installation manual to determine if you have on-board relays or the kind of outputs provided.

3 wire positive relay configuration

5 wire relay configuration

The following two documents provides some operations details and interface instructions.

3 wire positive tech sheet

5 wire tech sheet

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This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

Sorry, some of the confusion may have come from how I phrased the last post, and the rest of it came from my ability to see the forest through the trees.

I was commenting on the fact that I checked the switch to see which method of locking the truck had, as in some of the posts I have read throught the site, it was mentioned that if this year truck had both power locks and power windows, then it may have the 3 wire positive regardless of whether keyless entry was ordered. My point of the 5 wire comment was stating I didn't think this was the case. I will probe the wires to insure this is correct, but am pretty certain its the 5-wire reverse polarity

Where I had my brain fart was I was assuming that since I need to break the wire between the switch and the actuator, that is all in the door. Not realizing that there is an interface between doors, ala wires in the driver's kick panel with a twin realy set-up.

The unit I am using has (-) outputs for the door locks. If I am seeing this clearly (after verifying 5 wire reverse polarity locks), I will wire the realys such that poles 86/87 are +12V, poles 87a go to the switch side of the kick panel wire, poles 30 go to the acuator side of the kick panel wire, and ples 85 go to the remote starter output.

Do I have a good grasp on this? Or am I missing something? Can I use the 12+ that is feeding the door switches, or should I pursue another "hot" wire source?

Thanks again for your help as I (obvioulsy) have never wired one of these units before.

Sorry to add more to the confusion, but I did check a bit more at lunch on the unit. The unit is an Audiovox APS-55C. The outputs for the door locks are stated as (neg lock / positive unlock) on one wire, and the opposite on the other. Is this the flip/flop you are referring to? If so, do I still need a diode if I do not currently have keyless entry? Does my scenario described above still hold true (if it was correct to begin with), or does this change things?

The wiring scheme you have is correct. I do use the +12V wire going to the switch when interfacing a 5 wire system, but make sure you fuse the wire to the relay and not use it to power anything else. The only time I do not use this wire to power the relays is when the vehicle is equipped with a RAP type electrical system where the power is turned off after a predetermined time. Personally, I like to apply +12V to terminal 86 like you stated above instead of 85, just in case the relay used has a built in diode to suppress voltage spikes.

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This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

dkeys23 wrote:

Sorry to add more to the confusion, but I did check a bit more at lunch on the unit. The unit is an Audiovox APS-55C. The outputs for the door locks are stated as (neg lock / positive unlock) on one wire, and the opposite on the other. Is this the flip/flop you are referring to? If so, do I still need a diode if I do not currently have keyless entry? Does my scenario described above still hold true (if it was correct to begin with), or does this change things?

Yes this is what I mean by flip-flop. If you are using relays, you will not need diodes.

-------------
This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

Some comments if I may. There are no mistakes but 91st states the comment about 85 being the negative side of the relay coil, that's because the ISO convention and therefore ALL car manufacturers "go with the flow". It needles me that some alarm manufacturers and some of the diagrammes on this site flip 85 and 86 around, dangerous as 91ST noted because some relays do come with built in diodes.
The diodes are there to prevent damage to the circuits switching the relays at 85. It's a high voltage onrush spike that occurs when the relay coil shuts down. For this reason I would place diodes inline on your lock wires from the alarm, 1N4004, bands towards the alarm. In practise I would always do this when feeding out from flip-flop outputs, it conditions the alarm to flip rather than flop.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thanks once again for your help and insight. After drawing the schematic, I understand now with your help. I am a mechanical guy trying to survive in an electrical world.

What size fuse should be used for the relay +12v?

Actually, one more question other than the rated fuse size above. As I was re-reading the manual for the Prestige APS-55C, I have a question on the Ignition 3 output. I have seen 2 different data sheets for the 1997 Chevy 1/2 ton truck. One says needs this output, the other says it doesn't. Can anyone confirm whether this output is required on this truck? The manual says to hook it to a relay. Although it is describing a SPST relay, I have the bases covered after the discussions above.

Fuse size 20amps if 4 doors. TEST for third ignition, if so yes relay thus. 2nd ignition, branch to relay 86
Ground to 85
30amp constant 12V+ to 87
30 to third ignition.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

dkeys23 wrote:

Thanks once again for your help and insight. After drawing the schematic, I understand now with your help. I am a mechanical guy trying to survive in an electrical world.

What size fuse should be used for the relay +12v?

A relay is electro-mechanical, so your half way there ;)
I believe the factory fuse is 20A but there are a number of circuits fed by that fuse. I would not go bigger than 20A, I would err on the safe side and use 10A.

dkeys23 wrote:

Actually, one more question other than the rated fuse size above. As I was re-reading the manual for the Prestige APS-55C, I have a question on the Ignition 3 output. I have seen 2 different data sheets for the 1997 Chevy 1/2 ton truck. One says needs this output, the other says it doesn't. Can anyone confirm whether this output is required on this truck? The manual says to hook it to a relay. Although it is describing a SPST relay, I have the bases covered after the discussions above.

As a general rule for myself, any GM truck that I work on from 1995 on that has multiple ignition wires, I power all of them to avoid setting a DTC which may put the transmission in limp mode. Not doing so can cause more headaches and wasted time and money than connecting these wires.
Your 3rd ignition is a negative output so you must use a relay. Just wire the relay as follows:
30 = 3rd ignition wire of vehicle
87 = constant 12v
87a = not needed, get rid of the wire or insulate
85 = 3rd ignition output of r/s system
86 = constant 12v

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This information is provided only as a reference.
All circuits should be verified with a digital multi-meter prior to making any connections.

OK guys. I finally got around to installing the remote start / keyless entry unit. Everything went well on the remote start. It functions as intended. I wired up the 2 relays for the door locks and ran into an issue. The doors will unlock, but the fuse blows when I push the lock button. I will attempt to describe how I have it wired.

I have both relays pins 86 and 87 to a constant 12+ (all on the same source) fused with a 10A fuse. I have cut the LT blue lock wire at the switch (the harness was in the inner cowl and I couldn't access it so I ran a 4 wire lead into the door). Either end of this wire is connected to the 87a and 30 pins on the relay. The 85 pin is going to the keyless entry module. I have cut the White unlock wire at the switch and wired to the 87a and 30 pins of the other relay. As I'm typing I can't confirm which end is 87a and which is 30, but as I refer to a schematic, I can't see how that would make a difference.

As a check, I powered a continuity testor (to check for ground) and confirmed that the lt blue wire is ground until the moment the lock button is hit and the white wire has the same ground except when the unlock button is hit.

Does anyone have any ideas? Could this setup need a diode? Any help would be appreciated.

Thank you.

Change 30 and 87a around on the lock relay.
Because of the way the relay works 87a MUST go to the switch or car side and 30 MUST go to the motor (actuator) side.
If there are 2 locks I would go 15 amps, with 4 (i.e. side and or tailgate locks) I would go to a 20 amp fuse.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thank you for the response. That is exactly what the issue was and has been corrected. Can you please take a minute to explain to me why this direction matters?

If I look at the layout of a relay, the normally closed circuit supplied 12+ from 87 to 30. When I press the transmitter lock button, it supplies a ground to the negative side of the relay coil (85 & 86) which energizes the coil to swtich the poutput from 87 to 87a. This results in a closed circuit from 87a to 30. I guess I don't see how polarity is an issue. If someone could explain, that would be great.

Thanks to everyone that has helped with direction and/or advice.

Actually 87a is the normally closed circuit, 30 is the common and 87 is normally open, thus 30 continuous to 87a becomes 30 continuous to 87 when the coil is activated.
Polarity is only relevant across the coil, the ISO or SI labelling applies to all the terminals on a modern car just as the icons on your gauges are the same such as fuel, temperature, parking brake whether your vehicle was made in Kazakhstan or Detroit (Blazers are made on Kz!) or Tokyo.
The convention makes 85 the neg side and 86 the pos side. This is relevant for 1 reason. Some relays have built in diodes. The reason being that when the supply to the coil shuts down you get an "onrush" voltage spike. This can feed back to delicate chip or transistor circuitry and ruin it such as your alarm and R/S, been there and done that. The diode prevent this, in fact finally DEI recommend it with their 5901/2 series.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.